Create obfuscation-explorer project

[DenWav]

This is a separate plugin to support all different Java mapping formats. This plugin will provide a extension points for the Minecraft Development plugin to hook into and provide mapping information. It will also provide a generic settings page to allow users to configure their own mappings for the project.

As is this is incomplete, not ready to be used for anything really. However, it's a big change that doesn't currently change the base Minecraft Development plugin at all, so it's safe to merge to make it easier to work on going forward.