This makes it easier for downstream projects (forks) to replace the
version fetching system with their own. It is as simple as implementing
an interface and overriding the default implementation of
org.bukkit.UnsafeValues#getVersionFetcher()
It also makes it easier for us to organize things like the version
history feature.
Lastly I have updated the paper implementation to check against the site
API rather than against jenkins.
This was a useless exception wrapper that ends up making
stack traces harder to read as well as the JVM cutting off
the important parts
Nothing catches this exception, so its safe to just get rid
of it and let the REAL exception bubble down
