[receiver/vcenter] Adds Datacenter metrics (#33933)

**Description:** <Describe what has changed.>
<!--Ex. Fixing a bug - Describe the bug and how this fixes the issue.
Ex. Adding a feature - Explain what this achieves.-->
The following PR introduces multiple different metrics at a datacenter
level. It takes advantage of processing thats already done at the
cluster, host, vm, and datastore level in order to aggregate datacenter
level metrics.

```
- vcenter.datacenter.cluster.count                 status={red/green/yellow, gray}
- vcenter.datacenter.vm.count                      status={red/green/yellow, gray} power_state={on/off/suspended}
- vcenter.datacenter.datastore.count               status={red/green/yellow, gray}
- vcenter.datacenter.host.count                    status={red/green/yellow, gray} power_state={on/off/standby/unknown}
- vcenter.datacenter.disk.space                    disk_state={used/available}
- vcenter.datacenter.cpu.limit
- vcenter.datacenter.memory.limit
```

**Link to tracking Issue:** #33607

**Testing:** <Describe what testing was performed and which tests were
added.>
Tested against a live environment to make sure all values matched up.
Golden testing files have been updated.

**Documentation:** <Describe the documentation added.>
All documentation was generated through mdatagen

Author: BominRahmani

.chloggen/add_vcenter_datacenter_metrics.yaml

@@ -0,0 +1,28 @@
+# Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: enhancement
+
+# The name of the component, or a single word describing the area of concern, (e.g. filelogreceiver)
+component: vcenterreceiver
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: "Adds vCenter metrics at the datacenter level."
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [33607]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext:
+  Introduces various datacenter metrics which work by aggregating stats from datastores, clusters, hosts, and VM's.
+
+# If your change doesn't affect end users or the exported elements of any package,
+# you should instead start your pull request title with [chore] or use the "Skip Changelog" label.
+# Optional: The change log or logs in which this entry should be included.
+# e.g. '[user]' or '[user, api]'
+# Include 'user' if the change is relevant to end users.
+# Include 'api' if there is a change to a library API.
+# Default: '[user]'
+change_logs: [user]

receiver/vcenterreceiver/client.go

@@ -154,11 +154,13 @@ func (vc *vcenterClient) HostSystems(ctx context.Context, containerMoRef vt.Mana
 	var hosts []mo.HostSystem
 	err = v.Retrieve(ctx, []string{"HostSystem"}, []string{
 		"name",
+		"runtime.powerState",
 		"summary.hardware.memorySize",
 		"summary.hardware.numCpuCores",
 		"summary.hardware.cpuMhz",
 		"summary.quickStats.overallMemoryUsage",
 		"summary.quickStats.overallCpuUsage",
+		"summary.overallStatus",
 		"vm",
 		"parent",
 	}, &hosts)
@@ -210,6 +212,7 @@ func (vc *vcenterClient) VMs(ctx context.Context, containerMoRef vt.ManagedObjec
 		"summary.quickStats.swappedMemory",
 		"summary.quickStats.ssdSwappedMemory",
 		"summary.quickStats.overallCpuUsage",
+		"summary.overallStatus",
 		"summary.config.memorySizeMB",
 		"summary.storage.committed",
 		"summary.storage.uncommitted",

receiver/vcenterreceiver/documentation.md

@@ -72,7 +72,7 @@ The number of virtual machines in the cluster.
 
 | Name | Description | Values |
 | ---- | ----------- | ------ |
-| power_state | The current power state of the virtual machine. | Str: ``on``, ``off``, ``suspended`` |
+| power_state | The current power state of the virtual machine. | Str: ``on``, ``off``, ``suspended``, ``unknown`` |
 
 ### vcenter.cluster.vm_template.count
 
@@ -493,6 +493,88 @@ metrics:
     enabled: true
 ```
 
+### vcenter.datacenter.cluster.count
+
+The number of clusters in the datacenter.
+
+| Unit | Metric Type | Value Type | Aggregation Temporality | Monotonic |
+| ---- | ----------- | ---------- | ----------------------- | --------- |
+| {clusters} | Sum | Int | Cumulative | false |
+
+#### Attributes
+
+| Name | Description | Values |
+| ---- | ----------- | ------ |
+| status | The current status of the managed entity. | Str: ``red``, ``yellow``, ``green``, ``gray`` |
+
+### vcenter.datacenter.cpu.limit
+
+The total amount of CPU available to the datacenter.
+
+| Unit | Metric Type | Value Type | Aggregation Temporality | Monotonic |
+| ---- | ----------- | ---------- | ----------------------- | --------- |
+| {MHz} | Sum | Int | Cumulative | false |
+
+### vcenter.datacenter.datastore.count
+
+The number of datastores in the datacenter.
+
+| Unit | Metric Type | Value Type | Aggregation Temporality | Monotonic |
+| ---- | ----------- | ---------- | ----------------------- | --------- |
+| {datastores} | Sum | Int | Cumulative | false |
+
+### vcenter.datacenter.disk.space
+
+The amount of available and used disk space in the datacenter.
+
+| Unit | Metric Type | Value Type | Aggregation Temporality | Monotonic |
+| ---- | ----------- | ---------- | ----------------------- | --------- |
+| By | Sum | Int | Cumulative | false |
+
+#### Attributes
+
+| Name | Description | Values |
+| ---- | ----------- | ------ |
+| disk_state | The state of storage and whether it is already allocated or free. | Str: ``available``, ``used`` |
+
+### vcenter.datacenter.host.count
+
+The number of hosts in the datacenter.
+
+| Unit | Metric Type | Value Type | Aggregation Temporality | Monotonic |
+| ---- | ----------- | ---------- | ----------------------- | --------- |
+| {hosts} | Sum | Int | Cumulative | false |
+
+#### Attributes
+
+| Name | Description | Values |
+| ---- | ----------- | ------ |
+| status | The current status of the managed entity. | Str: ``red``, ``yellow``, ``green``, ``gray`` |
+| power_state | The current power state of the host. | Str: ``on``, ``off``, ``standby``, ``unknown`` |
+
+### vcenter.datacenter.memory.limit
+
+The total amount of memory available to the datacenter.
+
+| Unit | Metric Type | Value Type | Aggregation Temporality | Monotonic |
+| ---- | ----------- | ---------- | ----------------------- | --------- |
+| By | Sum | Int | Cumulative | false |
+
+### vcenter.datacenter.vm.count
+
+The number of VM's in the datacenter.
+
+| Unit | Metric Type | Value Type | Aggregation Temporality | Monotonic |
+| ---- | ----------- | ---------- | ----------------------- | --------- |
+| {virtual_machines} | Sum | Int | Cumulative | false |
+
+#### Attributes
+
+| Name | Description | Values |
+| ---- | ----------- | ------ |
+| status | The current status of the managed entity. | Str: ``red``, ``yellow``, ``green``, ``gray`` |
+| power_state | The current power state of the virtual machine. | Str: ``on``, ``off``, ``suspended``, ``unknown`` |
+
 ### vcenter.host.cpu.capacity
 
 Total CPU capacity of the host system.