feat(internal resources) - add the capability to declare some resources internal

Internal resources can be used only for data manipulation using the datalayer.
Thought so. It is cool but:
- should be renamed to post_internal (according to my dictionary intern is "a student or trainee who works, sometimes without pay, at a trade or occupation in order to gain work experience.")
- both `post()` and `post_internal()` should receive a docstring upgrade. in post() explain that this one is subject to auth and will fire pre_events. in post_internal() explain that you can call this one internally and won't raise etc. This is needed because in the future developer documentation (built from docstrings) there won't be decorators visible.