add new command to clean height hint cache.

[ziggie1984]

A new command is introduced to help noderunners suffering from the problem in https://github.com/lightningnetwork/lnd/issues/8028 where for reasons still not known yet the height hint cache for some spending notifications is poisoned with wrong data leading to unrecognized spends. A wrong height hint entry can lead to situations where channels are never resolved internally and the associated funds might also be stuck indefinitely.

This command should be a temporary fix until we find the real reason why invalid height hints are populated in the table.

How to use the new command:

In case you have channels which are still in the waiting_force_close state, just call the command in the following way:

chantools dropheighthintcache --channeldb channel.db

In case you want to rescan the blockchain for a specific output you need to execute the command in the following way:

chantools dropheighthintcache --channeldb channel.db --chan_point bd278162f9843311f64c76715c7a5c903c0467dc2c9f76af84ecbab00764c8a1:0