Update docs, add settings for adapter-specific config

Merge Request Checklist

• Link to an issue
• Include the proposed fix or feature
• Include and update tests for the modified code
• Include a documentation change
• Add a CHANGELOG.md entry in the Unreleased section for any user-facing changes
• Mention or assign a maintainer

Closes #3298 (closed)

This is dependent on these MRs for the new file bundles:

• https://gitlab.com/meltano/core-team/files-dbt-postgres/-/merge_requests/1
• https://gitlab.com/meltano/core-team/files-dbt-redshift/-/merge_requests/1
• https://gitlab.com/meltano/core-team/files-dbt-bigquery/-/merge_requests/1

Currently set to Draft: because I'm still testing (testing has turned out to be kind of a bear for this, since it involves setting up a warehouse of each type to test against), but as I don't anticipate significant changes during testing, and what changes may arise are likely to be in the file bundles.

MR-Specific Checklist

These tasks will need to be done before release so that the file bundles are accessible:

• Move files-dbt-postgres out of core-team/ and into top-level meltano group.
• Make files-dbt-postgres public.
• Move files-dbt-redshift out of core-team/ and into top-level meltano group.
• Make files-dbt-redshift public.
• Move files-dbt-bigquery out of core-team/ and into top-level meltano group.
• Make files-dbt-bigquery public.