Executions of 3rd party plugins directly users correct ClassLoader from the plugin class itself.

https://github.com/forge/core/blob/master/shell/src/main/java/org/jboss/forge/shell/command/Execution.java#L148

But since the ScaffoldPlugin, which is built in, and directly invokes Facets from plugins, it is actually actually still invoking within the context of the ScaffoldPlugin's ClassLoader, not that of the Facet.

We need a utility to more easily wrap invocations in the correct ClassLoader.