fix: multiple fixes to conditions we check while opening new connections

[UdjinM6]

Issue being fixed or feature implemented

Changes:

• c4819b9: we backported 15486 in backport: misc net backports #4213 incorrectly, feeler connections from the same net group should be allowed
• e5a19c3: fAllowMultiplePorts was introduced in Switch CNetFulfilledRequestManager and CMasternodeMan maps/funcs to CService #1967 to preserve the behaviour of the old non-deterministic masternode list while fixing netfulfilledman. Most of that code is gone because we use DMN now and fAllowMultiplePorts is kind of useless (and even confusing). Should be safe to drop it completely imo. Inspired by 6451dd7 in feat(net): add "system ports" and Bitcoin ports to "bad" ports list #6535.
• 47f47d8: there is no reason not to check MN addresses for required net services
• 8872ba3: we shouldn't break the loop if addr belongs to the set of already connected masternodes, should simply continue just like we do when we find addr from the same net group
• db7f4cf: should allow non-Dash-specific conditions to trigger first for better compatibility

What was done?

See above/individual commits

How Has This Been Tested?

• Run tests
• Run testnet/mainnet masternode for a day or two

Breaking Changes

It's now possible to have regular nodes with the same address but different ports on mainnet too but that's not a breaking change hopefully.

Checklist:

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have added or updated relevant unit/integration/functional/e2e tests
• I have made corresponding changes to the documentation
• I have assigned this pull request to a milestone