Allow enabling/disabling Incremental Prebuilds in a Project's settings

[jankeromnes]

Is your feature request related to a problem? Please describe

We have a feature called Incremental Prebuilds that can create new Prebuilds on top of older (compatible & successful) Prebuilds.

This feature can significantly speed up Prebuilds for projects that take > 10 minutes to build. (⚠️ For projects that take < 10 minutes to build, Incremental Prebuilds doesn't yield a significant speed-up and can actually even slow them down.)

However, only Gitpod developers can enable or disable it for specific repositories today (by editing server.incrementalPrebuilds.repositoryPasslist in this internal config file and re-deploying Gitpod).

Describe the behaviour you'd like

It would be great if users could opt-in or opt-out of Incremental Prebuilds directly from their Project's settings, e.g. with a checkbox like this:

Project Settings

• Use Incremental Prebuilds (beta)

Describe alternatives you've considered

Additional context

[gtsiolis]

Thanks for opening this, @jankeromnes!

FWIW, this was also brought up in a recent product sync meeting (internal). The consensus was also to go with a project settings option. Cc @jldec @atduarte @csweichel @svenefftinge

suggestion: I'd suggest to include some help text to describe what is this feature and how a project could benefit.

question: Could we detect whether this is suggested for a repository? For example, we could nudge users to enable incremental prebuilds when prebuilds for example take more than X minutes? Similarly, we could nudge users to disable the feature when prebuilds less than X minutes let's go with the first approach in the first iteration and get some data around usage. Does this make sense?

[jankeromnes]

Added self-hosted label as requested by @metcalfc 👋

[jankeromnes]

Happy to take this once once it gets scheduled.

[jankeromnes]

Proof-of-concept: https://github.com/gitpod-io/gitpod/compare/jx/incremental-prebuild-settings