[Feature] Support for meta in Dimensions, Entities, and Measures

[DevonFulcher]

Is this your first time submitting a feature request?

• I have read the expectations for open source contributors
• I have searched the existing issues, and I could not find an existing issue for this feature
• I am requesting a straightforward change to existing dbt-semantic-interfaces functionality, rather than a Big Idea better suited to a discussion

Describe the feature

Dimensiona, Entities, and Measures should have meta config like other dbt resources https://docs.getdbt.com/reference/resource-configs/meta.

Describe alternatives you've considered

No response

Who will this benefit?

This will provide consistency across dbt resources.

Are you interested in contributing this feature?

Yes.

Anything else?

I have already started on this here. The biggest open question is how to implement combining configs, such as here https://docs.getdbt.com/reference/configs-and-properties#combining-configs. This behavior is a bit confusing to me and there may be a problem with our docs our a bug in the implementation. For example, In this case, there is no meta_location_1 in the manifest:

sources:
  - name: source_1
    config:
      meta: {"meta_location": "source level1", "meta_location_1": "source level2"}

    tables:
      - name: table_1
        config:
          meta: {"meta_location": "table level3", "meta_location_2": "table level4"}

However, in this case there is:

sources:
  - name: source_1
    config:
      meta: {"meta_location": "source level1", "meta_location_1": "source level2"}

    tables:
      - name: table_1

So, it looks like these meta dictionaries aren't being merged as described in the docs.