Unify the scaffolding!

[gauron99]

We have made a few immediate fixes for parts of scaffolding which were necessary at the time. Now that we are past that, we can unify and cleanup the scaffolding code.

This issue covers *ALL of the scaffolding unification. This might be broken down into multiple PRs.
related work items:

• go scaffolding with buildpacks
• python injectors
• remote deployments

related #3005

/assign

[github-actions]

This issue is stale because it has been open for 90 days with no
activity. It will automatically close after 30 more days of
inactivity. Reopen the issue with /reopen. Mark the issue as
fresh by adding the comment /remove-lifecycle stale.