Document PeerManager::Options members.
Clamp -maxorphantx to uint32_t bounds.
Clamp -blockreconstructionextratxn to uint32_t bounds.
Also changes max_extra_txs into a uint32_t to avoid platform-specific behaviour.
-maxaddrtosend is hidden option used only for tests, so we only do minimal boundary checks.
This is a backport of core#28149