net_processing: move avalanche related args to PeerManager::Options

Summary:
This removes the PeerManager dependency on gArgs.

Non-backport follow-up to D16455

Depends on D16456

Test Plan: ninja all check-all

Reviewers: #bitcoin_abc, Fabien

Reviewed By: #bitcoin_abc, Fabien

Differential Revision: https://reviews.bitcoinabc.org/D16457