With the refactoring of the '3rd level' backend module
API, we can finally clean up the Template related
backend controllers.

Notable UI changes:
* There was a rather hidden functionality in the template
  module: The "Template record overview" that lists all
  pages that have sys_template records, is only rendered
  when the root page "Page zero" is selected. This can be
  hard to find and is contrary to all other backend modules
  where sub-functionality is selected using the drop down
  in the doc header. The patch changes this: The template
  record overview is now always shown as 5th element in the
  drop down. It currently renders the same output on all
  pages, but could be made page-aware later.
* The TypoScript Object Browser has a detail view to edit
  single properties, which then write to a sys_template
  record. This view also allows to add the edited path to
  an "Object List" if it has sub properties. This is
  remembered for the given user. The user can then select
  this path in the object browser tree view to limit the
  view to this section of the tree. All in all, this is a
  rather hidden and pretty much unknown detail functionality
  of limited use. This functionality has been removed.

Patch overview:
* Implement the "Template record overview" as new
  controller.
* Resolve "controller extends controller" inheritance and
  introduce an abstract controller with common methods of
  client classes. Methods don't add class state.
* Heavily reduce class state to a minimum.
* Improve separation of controller and view concerns.
* Split some templates to partials.
* Leverage dependency incjection correctly: Abstract uses
  inject* methods, client classes use constructor DI.
* Remove user access checks since the entire Template
  module is 'admin only', which is checked by middlewares.
* Various general clean ups, variable renamings, better
  structured methods.

Change-Id: I64cb7ea6275af491233ff7ee525c9260e5da6627
Resolves: #97591
Related: #97135
Releases: main
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/74550


Tested-by: core-ci <typo3@b13.com>
Tested-by: Stefan Bürk <stefan@buerk.tech>
Tested-by: Jochen <rothjochen@gmail.com>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Stefan Bürk <stefan@buerk.tech>
Reviewed-by: Jochen <rothjochen@gmail.com>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>