Consider a larger peer ID

[dgllghr]

Currently the peer ID is limited to a u64. To avoid peer ID collisions with a large number of peers (or needing some kind of central coordination for peer IDs), I would like to use UUIDs as peer IDs. Please consider increasing the size of the peer ID to u128 or [u8; 16].

[zxch3n]

Emm I think by using u64, the possibility of collision for a single CRDT document is low enough. The possibility of collision should be negligible even if there are 1M peers.