[6.0] Remove LegacyPropertyManagementTrait from MVC classes

[Hackwar]

Summary of Changes

The LegacyPropertyManagementTrait has been deprecated for quite some time and will most likely be removed in 7.0. This removes its usage from the base model and view classes of the CMS. This might look like quite a big break in b/c, but if you followed Joomla core code since Joomla 2.5, it isn't actually that big. We've not been using it anywhere really, except for the ->get() method in the views, which calls the methods from the models. However this has always been an overwritten method in the view anyway and it also still exists after this change. This means that all those old view classes will still work like before. The code from the trait has been deprecated since Joomla 3.4.0, even though it has been moved around and with Joomla 4.0 has finally ended up in the legacy trait. From my perspective, it is time to do this after 11 years of it being deprecated: https://github.com/joomla/joomla-cms/blob/3.4.0/libraries/joomla/object/object.php

Testing Instructions

Codereview.

Link to documentations

Please select:

• [ ] Documentation link for docs.joomla.org:

• [X] No documentation changes for docs.joomla.org needed

• [ ] Pull Request link for manual.joomla.org:

• [ ] No documentation changes for manual.joomla.org needed

[heelc29]

tests failing because its still used here https://github.com/joomla/joomla-cms/blob/f9ba37b8eda5fa6a2d8e237c1aa0ccae631acc6d/api/components/com_config/src/Controller/ComponentController.php#L83

[Hackwar]

Thanks, I removed that now.

[Hackwar]

Now that the documentation is also done, this one is ready for testing.