Full support for pruned nodes

[mononaut]

Bitfeed can run on a pruned node (#49), but the user experience is degraded and some features don't work.

Handling pruned data more gracefully would enable full support for pruned nodes.

• Friendly error message when a searched block or transaction is unavailable due to pruning.
• Fetch prevouts using gettxout instead of getrawtransaction for transactions in the mempool.
  • even if an ancestor transaction is pruned, the input we need is still stored in the UTXO cache.
    • (only works for mempool transactions)
• Special handling for pruned/unavailable inputs in the transaction details diagram
  • Label input address as 'pruned' or 'missing'
  • Label amount as 'unknown'
  • Set input line weight as the average unknown fee (i.e. share unused value equally across missing inputs)
    • Draw in a different color?

[SergioGlorias]

When the transaction without information that is in the mempool
the input is "unknown" and the fee paid does not appear due to not knowing
Note: when I wrote in #49, the screen also did not appear

on the other hand transactions he doesn't know and are already in the block he doesn't show anything

bitfeed-click-tx-in-block-unknown.mp4