[DOC] Add docs for otel logs source plugin

[lizsnyder]

What do you want to do?

• Request a change to existing documentation
• Add new documentation
• Report a technical problem with the documentation
• Other

Tell us about your request. Provide a summary of the request and all versions that are affected.

Requesting full documentation in the opensearch docs that cover the following plugin: https://github.com/opensearch-project/data-prepper/tree/main/data-prepper-plugins/otel-logs-source

[hdhalter]

Hi Caroline, this plugin is also going out with the OSI release in late April.