Limit the number of peers from which a single block will be downloaded

[ImplOfAnImpl]

Right now we don't have such a limit, so the node will download the same block from all connected peers that have it.

P.S. in bitcoin, the corresponding limit is MAX_CMPCTBLOCKS_INFLIGHT_PER_BLOCK, which equals 3 at this moment.

[TheQuantumPhysicist]

Keep in mind that compact blocks are a whole different thing. They're blocks that are partially filled from the mempool to optimize for bandwidth. Not particularly related to syncing from scratch.