Implement an `IpfsFileDownloader` in the client

[jpraynaud]

Why

Clients need to retrieve the immutable archives from IPFS using the directory CID published by the aggregator.

What

Implement an IpfsFileDownloader in the client that downloads immutable archives from a local IPFS node and restores them.

How

• Implement the IpfsFileDownloader (implements FileDownloader trait):
  • Connect the downloader to a local IPFS node
  • Download the immutable archives through the local IPFS node through the template and the directory CID
  • Uncompress the archive
  • Delete the compressed archive
  • Support feedback from local IPFS node