Add Simple Renamer example.

[LexManos]

Simple example of using the renamer plugin to build a obfusicated jar.
Addresses #3

Two main concerns I wanted to bounce of @Jonathing

1. This relies on having the mavenizer run, but currently doesn't invoke it in any way.
2. This also relies on the modder finding the mcpconfig version/parchment version. Which I can imagine now people geting confused about.

So basically, FG needs to make a couple helpers to get the mappings artifacts.
Not super critical, FD7 is the primary, but I think something like the Files object you're doing for that is probably something we could pull for this as well.