net processing: clamp PeerManager::Options user input

Summary:
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

Test Plan: ninja all check-all

Reviewers: #bitcoin_abc, Fabien

Reviewed By: #bitcoin_abc, Fabien

Differential Revision: https://reviews.bitcoinabc.org/D16456