[CT-3005] Support dictionary of additional configs in `dbt_project.yml`

[jtcohen6]

Housekeeping

• [X] I am a maintainer of dbt-core

Short description

Allow setting a dictionary of arbitrary configs in dbt_project.yml, which are to be read & used by dbt Cloud.

We don't need to validate the keys in this dictionary, nor store them in the project config class.

Let's call this dictionary dbt-cloud:

# dbt_project.yml
dbt-cloud:
  project-id: 1234
  ...

Acceptance criteria

It is possible to set a dictionary of arbitrary configs in dbt_project.yml, as metadata for dbt Cloud.

Impact to Other Teams

Cloud CLI impacted (see jira ink below), ensure this is completed within this sprint

Context

internal slack thread internal jira ticket

[graciegoheen]

Open question:

• how will they access these keys? are they intending on parsing these themselves?
  • via reading the dbt_project.yml file
  • yes, they would parse these themselves
• what should we name this?
  • let's go with ~cloud~ dbt-cloud

response discussed here and here