Add Actions, Refactor Stage / Guide Creation

# Why

In the spirit of small commits instead of monoliths, here are the first steps towards adding actions.

# What's changed
* Broke out a lot of the guide creation code which was largely just redundant success error statements into services on Angular. This needed to happen anyway.
* Did the same for stages.
* Add StageAction and ActionOption models, relevant factories
* Refactor create_stage mutation to use a hash
* Expanded some tests. 

# What's next

* Refactor update_stage to use a hash
* Save actions for each stage (probably similar to how images are validated and saved).
* Tests for those things
Mongoid defaults to string type, so you don't need to specify it (unless you just prefer to be explicit, which is fine, too).