[Nix] Auto start redis on nix develop

Summary:
Also start redis when doing nix develop

https://linear.app/comm/issue/ENG-1597

Depends on D4879

Test Plan:

# If you have redis setup through homebrew, then run:
brew services stop redis

nix develop

Should see:

View Redis Logs: tail -f $HOME/Library/Caches/Redis/logs
Kill Redis server: pkill redis

inspect logs:

tail -f $HOME/Library/Caches/Redis/logs

Reviewers: abosh, atul, varun, O1 Nix

Reviewed By: abosh, O1 Nix

Subscribers: atul, ashoat, tomek

Differential Revision: https://phab.comm.dev/D4880