Velocity Integration

[RemcoSpigot]

Describe the solution you'd like
Velocity Integration with automatic loadbalancing, service discovery and persistency. Clone of MultiPaper Master + Proxy but instead running MultiPaper Master as a Velocity Plugin.
Automatically switch the configuration values once switching from MultiPaper Master standalone to Velocity.
Make completely configurable.

Describe alternatives you've considered
None

Additional context
None

[RemcoSpigot]

Postponing until #13 is completely finished and ready for 1.18.2 and 1.19.2