feat: ✨ add RPC methods to use in maintenance mode

[TDemeco]

This PR adds the following RPC methods:

• remove_file_from_file_storage: Allows a Provider to manually remove a file that it's currently storing in its file storage. Useful when an issue made it so a file that's no longer in its forest was incorrectly kept in its file storage.
• add_files_to_forest_storage: Allows a Provider to manually add files to its forest storage.
  • It requires a forest key to know in which trie of the forest the files should be added, which means BSPs and MSPs can batch add multiple files in one call as long as they belong to the same forest key.
  • Useful when an issue made it so files that are currently in the file storage and should be part of a trie were incorrectly deleted from it or not added at all.
• remove_files_from_forest_storage: Allows a Provider to manually remove files from a trie of its forest storage.
  • It requires a forest key to know from which trie of the forest the files should be removed, which means BSPs and MSPs can batch remove multiple files in one call as long as they belong to the same forest key.
  • Useful when an issue made it so files that the runtime thinks were deleted are still in the forest and as such there's an inconsistency between the local forest root and the on-chain recorded one.

[ffarall]

Great job!