Github codespaces

[DimaAmega]

This pr allows us to use github codespaces feature

Just try to create a codespace on this branch and see what happens

The motivation:

• We can see deployment at any branch for a short period of time (about 30 minutes), but i believe this is fine for us
• Link to deployment may be public or private to organizations, which means that not only codespace creator can see deployment (see here) -- easy to share like "Look what I've done 👀"
• Speed up development process in some cases: instead of doing things locally like git stash && git checkout <some-branch> && <do-some-fixes-and-push-it> && git stash pop we can <do-some-fixes-and-push-it> in codespace (see here)
• some other ... 😊

The startup command for now is:

evidently ui --port 8000 --demo-projects all --workspace test-workspace