Add the option for users to specify on a per server basis if they want to use the old bungee cord forwarding method.

Or the new better one.

This would allow hybrid network of more secure newer servers.
And legacy support for older servers on the network.

e.g.
Server1:
-'Modern Skyblock 2'
bungeelegacy: true
Server2:
-'Vanilla1_15

For security it should either default to modern or autodetect,