[Feature] Allow for groups to have a description and/or meta field

[ttusing]

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 extension of existing dbt functionality, rather than a Big Idea better suited to a discussion

Describe the feature

Groups do not allow additional properties, like descriptions. This seems like a very obvious and helpful field to have. If there is no reason not to, why shouldn't groups support a meta property with whatever is helpful to save as well?

Describe alternatives you've considered

Not documenting my groups.

Who will this benefit?

Users of groups.

Are you interested in contributing this feature?

Yes

Anything else?

No response