Dockerfile UI build stage

[Itaykal]

Added a builder stage for the UI instead of doing it externally in a script.

[Itaykal]

I changed the docker cache type from gha to local, the Docker docs say that gha cache exporting is experimental.
Local has its own problems - The cache never clears itself so it must be removed, I added a step that does that as a temp fix

[Itaykal]

Drafting the PR, I have some testing to do with the cache, I want to see if it works as intended and expected

[Itaykal]

I changed the docker cache type from gha to local, the Docker docs say that gha cache exporting is experimental. Local has its own problems - The cache never clears itself so it must be removed, I added a step that does that as a temp fix

I tried to understand the differance between them and sounds like gha could be better, reverted

[Itaykal]

Disclaimer: The first run will be 30 minutes or so because nothing is cached