[CT-442] Productionize new adapter scaffolding

[leahwicz]

We want to start offering the new adapter scaffolding as the way to create new adapters instead of the existing script.

Tasks:

• Consume the new adapter testing framework
• Manual test runs and verification from a new set of eyes
• Polish work (i.e. are the docs in place, how do our tests and CI look, does the repo follow our best practices that are in place in dbt-core) - if this list is long, let's document it and split out the work
• Remove the old script and point to the new repo

CC: @McKnight-42 @ChenyuLInx let's pair on this

[McKnight-42]

List of various PR's open around this

• Docs changes for getdbt.com: Making changes to ref new adapter scaffold docs.getdbt.com#1362 (comment)
• Removal of old .py file: deleting scaffold and create_adater_plugin.py file from scripts section of core as they a… #5117 (edit: wound up leaving script mainly empty just with a print statement that will also lead users to new scaffold project as we allow transition period.)
• various small prs for Scaffold finalization: https://github.com/dbt-labs/dbt-database-adapter-scaffold/pulls