[receiver/sqlquery] sqlserver integration tests, improved coverage (#36922)

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#### Description

Mainly added test for sqlserver, plus added coverage for logs (as
requested in
[comment](#35195 (review)))

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#### Link to tracking issue
Fixes #29695

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#### Testing
Main changes:
* Added metrics tests for SqlServer
* Covered MySql, SqlServer and Oracle for logs

Improvements:

- To avoid repetitions, changed approach to "parameterized" tests - run
the same test flow for different database engines (for logs only).
- Do not hardcode "localhost" and host port, get these values from
testcontainers.
- Replaced inserting test values into the database from running CLI
commands in the container to executing SQL commands.
- Updated Oracle init script to use `otel` schema instead of `sys`.

Important: For Oracle and SQL Server, tests are **skipped** (tested
locally) - I expect them to fail due to #27577 (which was not fixed but
closed due to inactivity).
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Author: Grandys