Improved MVC events

[Denitz]

Summary of Changes

1. events_map property moved from FormModel to BaseDatabaseModel because the property is shared by multiple inheritors.
2. All eventClass params of AbstractEvent::create() calls are shortened to use Classname::class notation instead of using string event classname (easier to find all event class usages vide IDE in 2022).
3. onAfterDisplay event can modify the output now.
4. New ListQueryEvent class and onContentListQuery event to modify the list query before executing.
5. New AfterGetListEvent class and onContentAfterGetList event to modify the list of items after load from database.

Testing Instructions

1. Apply patch, try to play with custom events via your plugin, i.e.

		// All views return 'my custom HTML'
		public function onAfterDisplay(DisplayEvent $event)
		{
			$event->setArgument('source', 'my custom HTML');
		}

		// All lists are ordered by `a.id`
		public function onContentListQuery(DisplayEvent $event)
		{
			$event->getArgument('query')->order('a.id');
		}

		// All lists' titles are 'OK'
		public function onContentAfterGetList(AfterGetListEvent $event)
		{
			foreach($event->getArgument('list') as $item)
			{
				$item->title = 'OK';
			}
		}

Actual result BEFORE applying this Pull Request

Core Joomla is barely extendable.

Expected result AFTER applying this Pull Request

Core Joomla is extendable.

Documentation Changes Required

No.

[brianteeman]

Is this backwards compatible?

[nibra]

Looks good so far; I don't immediately see any b/c breaks. However, this PR should be targeted at 4.2, as it introduces a new feature.

[Denitz]

Is this backwards compatible?

@brianteeman Yes, it only adds the new functionality. I can add the same code in Joomla 3 but won't be accepted :)

[richard67]

@Denitz New functionality should go into 4.2, if backwards compatible. So this PR should be rebased to the 4.2-dev branch. Let us know if you need help with that.

After rebase, the PR might show unrelated changes on GitHub, but that will go away after the next update of the 4.2-dev branch with the latest changes on the 4.1-dev branch (so-called "upmerge") and after that an update of your branch for this PR to the latest 4.2-dev here.

[HLeithner]

There is a reason why we don't have a listquery event because it creates more then it solves. This has discussed several times.

Also the modification of the result is questionable. Because we easily generate more problems then expected.

[HLeithner]

Please remove the new Events for query manipulation, this has been discussed several times for more information look at #26179

[Denitz]

Please remove the new Events for query manipulation, this has been discussed several times for more information look at #26179

Sorry and thanks for your time. The query manipulation was the main feature of this PR.

[laoneo]

Would you mind to open a new pr which removes the hard codec class paths?

[Denitz]

I removed onContentListQuery event, though I totally disagree.

[joomla-bot]

This pull requests has been automatically converted to the PSR-12 coding standard.