Implement GET /v3/processes

* Separate domain and data access using separate models
* ProcessHandler will access the data object and return a domain object

[#79386676]
Implement POST /v3/processes

* ProcessHandler can new up a process domain object
* ProcessHandler persists process domain objects

[#79386676]
Implement DELETE /v3/processes/:guid

* Returns 404 if not authorized or not found
* ProcessHandler will noop on a non persisted process

[#79386676]
Implement PATCH for /v3/processes and inject ProcessHandler

[#79386676]
Rename ProcessHandler to ProcessRepository

[#79386676]
Change ProcessRepository to create an App instead of a ProcessModel

- ProcessModel was a straight copy-paste of App
- For this story a ProcessModel is unnecessary, so we decided to punt on
it for now.

[#79386676]
Add unit test coverage for ProcessesController and ProcessRepository.

[#79386676]
Add pretty printing to ProcessController responses and API documentation

[#79386676]
Bump errors submodule

[#79386676]