Rewrite NetworkManager and incorporate various fixes from open PRs

[Shadowghost]

I tried debugging and fixing a problem but didn't understand all the custom code, so I reimplemented the NetworkManager functionality with native .NET IPAddress and IPNetwork and a way more simpler object to hold both (e.g. for interfaces or in case we allow IPs and Subnets in a config)

Changes

• Migrate to native .NET IP objects and functions
• Incorporate changes from Multiple IP fixes #5595
• Fix LocalAddress resolution in System/Info/Public
• Remove hack for .NET issues resolved in .NET 6
• Remove invalid hack for X-Forwarded-For headers when IPv6 is enabled
• Remove unused configuration values from network settings
• Group network settings by functionality (this only affects how they appear in network.xml)
• Handle subnets in KnownProxies
• Removed UdpSocket and replaced it with native .NET sockets
• DLNA/SSDP and AutoDiscovery now only bind to valid bind addresses (WIP)

Notes

• DLNA does not require IPs in the Location prop but a lot of clients do not work with domains, therefore we force IP+port
• DLNA and SSDP still only support IPv4

Issues

• Additional testing is welcome, especially DLNA/SSDP and AutoDiscovery

Related
Fixes #6272
Fixes #9298
Fixes #9300
Partially fixes #8692
Might fix #4442
Might fix #7791
Might fix #9298
Might fix #9445
Might fix #9540
Might fix #9586

[joshuaboniface]

🚀

[Shadowghost]

There goes the 1 year PR anniversary 😢

[Bond-009]

I'd also add constants for the number of bits and bytes in IPv4 and IPv6 addresses

[Bond-009]

Suggested change

	if (negated && ipBlock.StartsWith("!") && IPAddress.TryParse(ipBlock[1..], out var tmpAddress))
	if (negated && ipBlock.StartsWith('!') && IPAddress.TryParse(ipBlock[1..], out var tmpAddress))

[Shadowghost]

This does not work: cannot convert from 'char' to 'System.ReadOnlySpan<char>'