Add option to drop some Gitpod layer metadata

[RDIL]

When building workspace images, Gitpod does this dumb process of modifying the bashrc file to add some configuration which doesn't need to exist assuming the image already does it.

If you want a more comprehensive idea on why this is extremely flawed, please see #1555.

My proposed solution

Add an empty file to all images that are meant explicitly for gitpod, like /bin/.is-gp-image.metadata, and if this file exists, then only add the declaration of user-set environment variable in Gitpod settings, and nothing else, assuming the image has the rest pre-configured, but if the file does not exist, add all the existing bashrc changes.
If a file doesn't work, maybe then just a list of image names that exclusively want to opt-out of this metadata addition.

Any thoughts @jankeromnes ?

I feel like this should be simple enough to implement.

[sr229]

We could use LABELs and parse them to automatically configure the container post-pull since this would allow us to use standard container features that are already builtin.

[RDIL]

Any updates on this? Its still super annoying.

[stale]

This issue 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.

[RDIL]

Still really want this.

[stale]

This issue 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.

[jankeromnes]

FYI, the problematic Gitpod layer has been entirely removed in #4923