[processor/tailsampling] allow setting only min_value or max_value for the numeric_attribute

[bmbferreira]

Description

This PR makes the numeric_attribute more flexible and allows to set only min_value or max_value, without the need to set both. This is useful to have simple configurations like these:

{
  type: numeric_attribute,
  numeric_attribute: {
    key: http.status_code,
    min_value: 400
  }
}

Link to tracking issue

N/A

Testing

Added unit tests to cover all changes and scenarios.

Documentation

I fixed an example on the documentation to have just the min_value set

[bmbferreira]

I've put it on draft because some things are still missing from the contributing guide

[bmbferreira]

I've put it on draft because some things are still missing from the contributing guide

fixed the remaining issues and it's ready for review now.

[github-actions]

This PR was marked stale due to lack of activity. It will be closed in 14 days.

[jpkrohling]

Thank you!

[bmbferreira]

Thank you!

🙏 obrigado