[Ingest Manager] Add metadata to system package

[mostlyjason]

Describe the feature:
We had a previous issue to add metadata to the index templates populated by Ingest Manager #70235. However, the base package was removed so the default templates don't get it. Let's also add the metadata for managed-by to the default templates as well.

Describe a specific use case for the feature:
We have two use cases that would benefit from adding metadata to our ES assets like index templates. The first is to identify assets we create to ES UI so we can provide users a visual indicator that these assets are managed by Ingest Manager. We can also provide a warning to users who attempt to change those assets that things could change when an integration package is updated. #69573. The second use case is for telemetry on which integrations are most popular in terms of data generated. We are aiming to get this in 7.9 since some of the telemetry work depends on it.

[elasticmachine]

Pinging @elastic/ingest-management (Team:Ingest Management)

[mostlyjason]

May need to ask ES team to help elastic/elasticsearch#57629

[mostlyjason]

Nevermind closing this one because I'm not sure its a good idea to consider all data in logs-- as managed by ingest manager, particularly for agent standalone mode where ingest manager is not even used.