Added btcmonitor to list of Utilities

[afalk42]

I recently created a new terminal dashboard (TUI) that monitors a local Bitcoin Core node using its JSON-RPC interface.

• Cross-platform using Python3 and Rich: tested on macOS, Ubuntu, Windows
• Uses cookie auth detection or bitcoin.conf as well as optional command-line parameters for rpc authentication
• Visualizes the following data about your bitcoin node in a dashboard:
  • Node health, blockchain height, peer information
  • Bitcoin price, block subsidy, # of blocks until next halving, time since last block
  • Mempool transaction count, memory size and fee histogram
  • Next block template as well as expected tx count, weight, and fee rate bands
  • Scrollable list of the 100 largest transactions in the mempool sorted by BTC output