Unconfirmed transcations: Identify and display "dead" transactions

[kokahunter]

Some nodes seem to have unconfirmed transactions in their mem polo that never get confirmed. That pushed the unconfirmed transaction count to a higher number than the actual transactions per block.

Currently displaying ~200 unconfirmed transactions every block. Avg transactions per block is at ~7-8 tx right now.

To archieve this:

• Monitor unconfirmed transactions for every block. If one tx hash shows up in the following n blocks it can be considered "dead"
• Dead unconfirmed tx can be displayed with a note and explanation
• If dead unconfirmed tx number is steadily rising, one node may have a problem and could potentially run out of memory. Node owners can monitor their node and take actions if needed.

[i25959341]

Look great, we could implement those three features by next week. It seems like it is very useful to the community

[i25959341]

We could have a separated component in the UI for dead transactions and the nodes counts

[kokahunter]

Great! Excited to see results!