API: Replace all withAPIData usage and deprecate the HoC

[youknowriad]

This PR removes the remaining usage of withAPIData from Gutenberg and officially deprecate its usage.

Testing instructions

• Check that The lastest posts block is working properly
• Check that you can set a parent page when creating pages.

closes #7397
closes #6277
closes #6379
closes #6537

[gziolo]

We are going to fetch more data, is that expected?

[youknowriad]

yes, with a central store like we do right now, we can't fetch a small part of objects, we fetch the whole objects or we don't. Because the redux state always expects the full object.

[gziolo]

We could, but it is super complex :)

[gziolo]

Eslint complains

/Users/gziolo/PhpstormProjects/gutenberg/core-blocks/latest-posts/edit.js
4:10 error 'get' is defined but never used no-unused-vars

Unit test fails:

● withAPIData() › should initialize fetchables on mount

expect(jest.fn()).not.toHaveWarned(expected)

Expected mock function not to be called but it was called with:
["wp.components.withAPIData is deprecated and will be removed from Gutenberg in 3.7. Please use the Core Data Module or wp.apiFetch directly instead."]

  26 |      afterEach( () => {
  27 |              if ( spy.assertionsNumber === 0 && spy.mock.calls.length > 0 ) {
> 28 |                      expect( console ).not[ matcherName ]();
     |                      ^
  29 |              }
  30 |      } );
  31 | };

  at Object.<anonymous> (packages/jest-console/src/index.js:28:4)

Otherwise everything works perfectly fine.

[gziolo]

Awesome 🎉

great one 💯

[aduth]

Nit: The function returns a promise. The promise resolves to a list of the taxonomies entities.

Aside: This is probably one of the only things I dislike about async / await, that it becomes very non-obvious that it will always return a Promise (I think even if the function has no return statement? My uncertainty reenforces my point 😄 ).