This diff replaces the utxos structure in the peer manager with the UtxoStore.
This store is configured with a limited depth of a single proof per utxo, and the proof utxos attachment is made so that there is no change in behavior.
The utxos attachement call is moved from `createPeer()` method to the `registerProof()` as it is about proof and not peer.
Ref T1854.
Depends on D10453 and D10459.