v0.4.0: Babidi Somniosidae

New requirements:

• Changes bitcoind minimum supported version to 22.0

Features:

• Bitcoind version is now checked at startup
• The bitcoind poller rescans from the latest tip, so we won't
  miss any historical vault (this holds for reorgs too)
• We now exchange signatures with the watchtowers in a single batch
• A participant_type field was added to the getinfo result
• The hex field of the listpresignedtxs result was removed
• Add cpfp_amount and miner_fee to gethistory events
• Add status, cpfp_amount, cpfp_index and change_index to
  getspendtx and listspendtxs entries

Fixes:

• Avoid a race condition between the signature fetcher thread and the
  bitcoind poller thread upon reorg