Puppet Server Should Allow Configuring the Amount of Heap That JRuby Utilizes

It is my current understanding that puppetserver ships with a 512MB heap size for JRuby.

This is separate from the heap size for puppetserver as a whole and as such makes running puppet server on around or less than 512MB of RAM nearly impossible.

The amount of heap size for JRuby specifically should be configurable if possible.