[api] move code to find the default reviewers into the model
[api] move generation of patchinfo in the project model
[api] move the complete permission check in a function on its own

Using functions of the request and the action model
[api] have a subclass for each request type

This is just a rename of the column name, but this allows in the future
to have functions overload per type
[api] move action type specific code from the controller into the models