net: Add CNodeOptions and increase constness

Summary:

net: make CNode::m_permissionFlags const

net: make CNode::m_prefer_evict const

This is a partial backport of core#25962
https://github.com/bitcoin/bitcoin/pull/25962/commits/9dccc3328eeaf9cd66518d812c878def5d014e36 (partial, for struct CNodeOptions and the CNode ctor signature)
https://github.com/bitcoin/bitcoin/pull/25962/commits/d394156b99d6b9a99aedee78658310d169ca188d
https://github.com/bitcoin/bitcoin/pull/25962/commits/0a7fc428978c4db416fdcf9bf0b79de17d0558d7

The first commit of the PR (i2p_sam_session) is not applicable due to missing backports.

Depends on D17109

Test Plan: ninja all check-all

Reviewers: #bitcoin_abc, Fabien

Reviewed By: #bitcoin_abc, Fabien

Subscribers: Fabien

Differential Revision: https://reviews.bitcoinabc.org/D17110