lightning-liquidity: Eventually archive or remove persisted state #4084
Description
After #4059, we'll start persisting the handler states to our KVStore.
However, we haven't fully figured out an API that would allow to archive or remove the persisted state from the KVStore again. Currently, any expired/pruned states would be re-read on restart and then pruned again. As the KVStore operations would also require an async context, we could consider to drive the regular pruning only based off the async fn persist calls.
It's however also not entire clear to me yet whether we shouldn't rather leave removal to the user, as they might want to keep some historical record of the JIT channel flows around.