Limit disk space #59
Description
If disk space is exhausted, hmq is not operational. It should handle this gracefully:
- define limit for "functions" and "tasks" collection in GB as environment variable
- upon function insert or result insert or dequeue, fail if limit is reached
- dashboard: show current usage
- make sure collections are autocompacted
- implement CLI "hmq archive" and "hmq archive --delete-after" which downloads all tag data and delete the downloaded tasks afterwards if the flag is given.