Directory .stellation grows with no pruning of old builds and logs

[Rek-Malorm]

Directory .stellation grows with no pruning of old builds and logs

When actively developing with a live server, a new build is produced for every change. One build for Frontend, one for Backend.
Frontend & Backend directories contain logs and a directory containing serve-builds.

If Autosave is enabled, this directory can quickly bloat with old builds and requires manual clearing. Without clearing, the directory quickly fills the available space until the server crashes.

[futursolo]

I have merged #149, which will be able to remove stale builds for stctl serve and stctl build.
Existing old builds can be cleaned with stctl clean.

I have kept old logs for the moment as it should not be very big.
Logs for stctl watch should eventually be printed to stdout and stderr once #4 is solved, which it will no longer be saved to files.