`ghcup gc` command (garbage collect)?
We could:
- remove GHC versions that have the tag
old
- remove profiling libs, which are automatically installed by ghc bindists
- remove GHC versions that don't have a cabal store
- remove HLS binaries that don't have a corresponding GHC version installed
- clean up the ghcup cache
- ...?
This could be interactive in the TUI and non-interactive via various switches in the CLI.