Name fibers for easier debugging

In this patch set:

• name proc fibers
• prefix stored procedures names raft_join and raft_interact
• name pool workers fibers
• reduce pool workers logging

Log example:

i2  | 2022-11-22 10:29:33.057 [1452033] main/116/raft_main_loop V> broadcast, event: raft.status-changed
i2  | 2022-11-22 10:29:33.057 [1452033] main/117/governor_loop I> processing i1 Online(1) -> Offline(1)
i2  | 2022-11-22 10:29:33.057 [1452033] main/117/governor_loop I> skip proposing replicaset master change                                                         
i2  | 2022-11-22 10:29:33.057 [1452033] main/117/governor_loop I> calling rpc::sharding, instance_id: i2                         
i2  | 2022-11-22 10:29:33.057 [1452033] main/155/to:i2 V> established connection to peer, raft_id: 2, peer: 127.0.0.1:3302                         
i2  | 2022-11-22 10:29:33.058 [1452033] main/131/proc_sharding I> Starting reconfiguration of replica 24c4ac5f-4981-3441-879c-aee1edb608a6