Extracted page editor view data gathering to its own class for
alignment. Updated the data used in views as part of the process to use
view-specific variables instead of custom attributes added to models.
Also moved tinymce library loading so it's not loaded when not using the
wysiwyg editor.
Updated the back button to be a proper link instead of a reference to
the last viewed URL since it could break if the last page was the
current one (On validation for example).
Includes test to cover.
Also applied some styleCI changes.
Fixes#2834
- Primarily moved and re-organised view files.
- Included readme within views to document the convention.
- Fixed some issues with page field select list in previous commit.
- Tweaked some route names while going through.
- Split some views out further.
Closes#2805
