p2p, refactor: make NetPermissionFlags a uint32 enum class

Summary:
https://github.com/bitcoin/bitcoin/pull/21506/commits/7b55a9449778c5ac89799ce4c607c8c8d797ddfb

p2p: NetPermissions::HasFlag() pass flags param by value

https://github.com/bitcoin/bitcoin/pull/21506/commits/810d0929c1626bba141af3f779a3c9cd6ece7e75

p2p, refactor: make NetPermissionFlags a uint32 enum class

and define/update operation methods to handle type conversions explicitly. See
https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#Renum-oper
for more info.

This eliminates the class of bugs like D13323

This concludes backport of core#21506
Depends on D13326

Test Plan: ninja all check-all

Reviewers: #bitcoin_abc, Fabien

Reviewed By: #bitcoin_abc, Fabien

Differential Revision: https://reviews.bitcoinabc.org/D13325