Dark theme rework

[silverwind]

List of things I plan to do:

• Remove THEMES option to allow us to easily introduce new themes. This currently acts as a whitelist so new themes can currently not be introduced without a config change and I don't really see a valid reason why admin would want to disable certain themes (theme is a user's choice, not admin's).
• Figure out webpack multi-stage webpack build where theme generation can run after public files have been written (essentially running webpack twice).
• Resolve Monochrome color special rule silverwind/remap-css#3 for easy remapping of monochrome colors.
• Auto-generate arc-green using remap-css.
• Possibly add new gitea-dark theme.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. I am here to help clear issues left open even if solved or waiting for more insight. This issue will be closed if no further activity occurs during the next 2 weeks. If the issue is still valid just add a comment to keep it alive. Thank you for your contributions.

[silverwind]

Not stale

[silverwind]

I'm thinking it may be time to put arc-green to the grave once we have the "proper" dark theme and migrate users to that new theme.

[silverwind]

#12448

[yardenshoham]

@silverwind is this completed?

[silverwind]

No, but I guess part of this stuff is now out of date, so I'll close it. I still would like to make a "darker" dark theme at some point, which should now be very easy since all colors are in variables.