Move Schemas to their contexts

[zacck-zz]

Enhancement

Phoenix 1.3 presents us with a powerful option (Contexts) to use when modelling our application, In lieu of separating a model of your application, we would use Contexts to arrange our code and share the functionality.
More on this see this video https://www.youtube.com/watch?v=tMO28ar0lW8

Work Proposed

Move schemas from lib/schemas to their respective contexts

Done

When we can agree on how to arrange the code

[coderberry]

@zacck we just moved the schema files into its own namespace for cleanliness. I don't think moving them back makes sense currently.

[zacck-zz]

Seems I based this on the assumption that we were separating the schemas to set the model aside