Was done for convenience but could potentially be exploited by an
attacker using signing up via one of these routes, then forwarding
an email confirmation to another user so they unknowingly utilise
an account someone else controls.
Tweaks the flow of confirming email, and the user invite flow.
For #3050
Also continued a bit on the MFA verification system.
Moved some MFA routes to public space using updated login service to get
the current user that is either logged in or last attempted login (With
correct creds).
* Started mass-refactoring of the current entity repos
* Rewrote book tree logic
- Now does two simple queries instead of one really complex one.
- Extracted logic into its own class.
- Remove model-level akward union field listing.
- Logic now more readable than being large separate query and
compilation functions.
* Extracted and split book sort logic
* Finished up Book controller/repo organisation
* Refactored bookshelves controllers and repo parts
* Fixed issues found via phpunit
* Refactored Chapter controller
* Updated Chapter export controller
* Started Page controller/repo refactor
* Refactored another chunk of PageController
* Completed initial pagecontroller refactor pass
* Fixed tests and continued reduction of old repos
* Removed old page remove and further reduced entity repo
* Removed old entity repo, split out page controller
* Ran phpcbf and split out some page content methods
* Tidied up some EntityProvider elements
* Fixed issued caused by viewservice change
