Rename EntityFormController to EntityForm

This does the following:

- Rename all *FormController classes and interfaces to *Form
- Renames getFormController() to getForm() on EntityManager
- Renames text references like "form controller" to just form.

Exceptions:
- There are a bunch of FormController classes that are actually controllers that then display a form.
- There are a few controller classes referenced to as "Temporary form controller", which means that are temporary wrappers that call to the FormBuilder for an old-style function based form.

Let's see what I missed. This was much less worse than I feared because, while we have a lot of form controller classes, we have almost no references to getForm() and those classes outside of the entity annotations.

Yes, @timplunkett also said that in the parent issue. EntityFormInterface implements FormInterface...

We have \Drupal::formBuilder()->getForm() to which you can pass an object that implements FormInterface (which would imply that an implementation of that interface is a "form"?), you get the form from a form? So we really already have that double meaning of "Form"?

And we have EntityFormBuilder::getForm(), to which you pass an entity and an operation and it gives you the form, using EntityManager::getFormController() internally, and yes, changing that to getForm() as well is weird.

Looking at the documentation of FormBuilder.:getForm():

   * Gets a renderable form array.
   *
   * @param \Drupal\Core\Form\FormInterface|string $form_arg
   *   The value must be one of the following:
   *   - The name of a class that implements \Drupal\Core\Form\FormInterface.
   *   - An instance of a class that implements \Drupal\Core\Form\FormInterface.
   *   - The name of a function that builds the form.

I would seriously argue that it's rather that method that is misnamed? :) Because that returns the result of buildForm(), and how can a method getForm() that returns an object implemting FormInterface be misnamed? :)

Anyway, I guess we can't change that, so I'm open to ideas? Note that there's almost zero usage of that method...

Re-rolled.

@andypost: That has nothing to do with this rename.

Discussed this a bit with @timplunkett as well, looks like everyone is onboard, can we move forward?

getFormObject() it is. Verified that unit test coverage annotations are still correct (there are bugs but not for entity manager.

10: entity-form-controller-rename-2238077-10.patch queued for re-testing.

Updated https://drupal.org/node/2200867, re-roll, issue summary written.

Forgot the comment. Did a re-roll too, and when comparing the files, noticed a few mistakes both in my re-roll and the one from @alexpott, fixed both, see manual interdiff.

Came back green, back to RTBC.