Nest Macro node `meta` under `config`

[QMalcolm]

Housekeeping

• I am a maintainer of dbt-core

Short description

The old/deprecated way of having meta was putting it directly on a node. However, awhile back we deprecated that paradigm and moved to nesting meta under a node's config. For reasoning I am not aware of, this never made it to Macro nodes. We should begin supporting the "best practice" path

Acceptance criteria

• Macro nodes have a meta property under their config property
• During parsing, flat meta specifications should end up under the config.meta

Suggested Tests

• Macro meta can be specified in the dbt_project.yaml config specification
• In a macro definition, people can specify meta directly on an macro or under a macro's config, both should end up in the macro's config.meta

Impact to Other Teams

Change impacts Artifacts team (change to the artifacts)

Will backports be required?

No

Context

No response

[QMalcolm]

@jtcohen6, exact same question as on #9446. I noticed on #7440 you mentioned in a comment that we intentionally didn't move meta under config for a subset of node types. Would you be able to speak to why that was? I know we did this intentionally, but without the context it at first looks like an inconsistency.

[dbeatty10]

See also:

• Demonstrate and explain config meta key nesting docs.getdbt.com#3710

[graciegoheen]

This just came up again here - #12383