Live-reload CLI projects on file changes

[schnie]

Today DAG files are "reloaded" when they are saved locally because we mount the files from the host filesystem into the containers. This does not work for Dockerfile, packages.txt, or requirements.txt, etc. We should fix this.

Good inspiration for this is tilt (probably without the dedicated UI for now). Tilt CLI experience to start.

https://tilt.dev/