Allow manually disabling prebuilds for a project

[jankeromnes]

Description

Allow manually disabling prebuilds for a project.

Related Issue(s)

Fixes #15281

How to test

1. Create a project, but don't enable prebuilds
2. Push a new commit to the project's repository
3. There should be zero prebuilds in the project

Release Notes

Allow manually disabling prebuilds for a project

Documentation

Werft options:

• /werft with-local-preview
  If enabled this will build install/preview
• /werft with-preview
• /werft with-large-vm
• /werft with-integration-tests=all
  Valid options are all, workspace, webapp, ide, jetbrains, vscode, ssh

[werft-gitpod-dev-com]

started the job as gitpod-build-jx-disable-prebuilds.3 because the annotations in the pull request description changed
(with .werft/ from main)

[jankeromnes]

/werft run cert-issuer=letsencrypt recreate-preview

👍 started the job as gitpod-build-jx-disable-prebuilds.6
(with .werft/ from main)

[jankeromnes]

/werft run cert-issuer=letsencrypt recreate-preview

👍 started the job as gitpod-build-jx-disable-prebuilds.8
(with .werft/ from main)

[jankeromnes]

/werft run

👍 started the job as gitpod-build-jx-disable-prebuilds.12
(with .werft/ from main)

[jankeromnes]

Okay, the UI is quite "basic" -- but now it works! 🎉 😁

New Project	Project Settings

If you uncheck this (during project creation or in a project's settings), no new prebuilds will be triggered for that project (whether from a repository push or from a "Run Prebuild" button click).

Now we "just" need:

• a good description text for the checkbox
• a UX review
• to decide what should happen to the other prebuild options if prebuilds are disabled
  • (though: what about turning the "Enable Prebuilds" checkbox into a toggle switch in the project settings, and then completely hide all other options when the switch is disabled?)

@gtsiolis @jldec and/or @selfcontained -- if you're not currently on holidays, would you mind giving this a quick look & sharing your thoughts? 👀 🙏

[gtsiolis]

/werft run

👍 started the job as gitpod-build-jx-disable-prebuilds.16
(with .werft/ from main)

[stale]

This pull request has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.