Cleanup unexpected immutable files in archive in client

[jpraynaud]

Why

We want to avoid restoring immutable files which have not been certified by Mithril but are in the artifact archive: the maximum immutable file number restored should be lower than the target immutable file in the beacon.

What

Add a cleanup phase of the immutable files in the client.

How

• Identify the immutable files which have been downloaded and should not be part of the archive:
  • Cardano DB v1
  • Cardano DB v2
• Remove those files if any
  • Cardano DB v1
  • Cardano DB v2
• Display a warning message explaining that some files were unexpected and deleted
  • Cardano DB v1
  • Cardano DB v2
• Run the cleanup phase even if an error occurs or alternatively remove the target directory?
  • Cardano DB v1
  • Cardano DB v2
• Make sure that the files are not kept in the Trash?