[5.0][RFC][Events] Make captcha plugins use plugin events

[Fedik]

Pull Request for Issue #28800 .

Summary of Changes

The patch improve Captcha plugins.
Now it can use a real events, and people stop confusing onDisplay (etc) callback with event.

How this work.
Here added a new event onCaptchaSetup and an Interface for CaptchaProvider class.
While this event the plugin should register own CaptchaProvider class in CaptchaRegistry.
The system will retrieve the requested Captcha type from that registry and call required methods, that defined by CaptchaProviderInterface

This is fully backward compatible.

Looking for feedback.
If all good we can do the same for Editor and its Buttons.

Techicaly now one plugin can provide multiple captcha, however for now the global configuration done per plugin.
But this can be extended in future, when need.

Testing Instructions

Apply patch, remove administrator/cache/autoload_psr4.php
Enable recaptcha_invisible and make sure it works.

Testing B/C:
Enable older recaptcha and make sure it works.

Actual result BEFORE applying this Pull Request

All works

Expected result AFTER applying this Pull Request

All works

Link to documentations

Please select:

• Documentation link for docs.joomla.org: https://docs.joomla.org/Plugin/Events
• Pull Request link for manual.joomla.org: Captcha plugin Manual#96

[dgrammatiko]

@Fedik could you also move the captcha plugin to service providers, like #39639

[Fedik]

Sure, will update later.

[laoneo]

@Fedik could you also move the captcha plugin to service providers, like #39639

I would do this in a separate pr to not block each other.

[dgrammatiko]

Sure, will update later.

Probably leave that for another PR. I'm waiting for the Editors, EditorsXtd version

[laoneo]

I guess it is better to rebase this pr to the 5.0-dev branch, as it will get more attention for new features. Thanks for understanding.

[HLeithner]

thanks