[5.2] [PHP8.4] Update for nullable type declaration

[heelc29]

Summary of Changes

updates for https://wiki.php.net/rfc/deprecate-implicitly-nullable-types

Testing Instructions

at the moment no QA release of PHP8.4 ... so only code review (and phpcs by drone) PHP 8.4.0 Alpha 1 available for testing

Actual result BEFORE applying this Pull Request

Warning:

Deprecated: Joomla\CMS\Application\AdministratorApplication::__construct(): Implicitly marking parameter $input as nullable is deprecated, the explicit nullable type must be used instead in libraries\src\Application\AdministratorApplication.php on line 74

Deprecated: Joomla\CMS\Application\AdministratorApplication::__construct(): Implicitly marking parameter $config as nullable is deprecated, the explicit nullable type must be used instead in libraries\src\Application\AdministratorApplication.php on line 74

Deprecated: Joomla\CMS\Application\AdministratorApplication::__construct(): Implicitly marking parameter $client as nullable is deprecated, the explicit nullable type must be used instead in libraries\src\Application\AdministratorApplication.php on line 74

Deprecated: Joomla\CMS\Application\AdministratorApplication::__construct(): Implicitly marking parameter $container as nullable is deprecated, the explicit nullable type must be used instead in libraries\src\Application\AdministratorApplication.php on line 74

[...]

Expected result AFTER applying this Pull Request

No new deprecated warnings (excepted composer dependencies) if update to PHP8.4

Link to documentations

Please select:

• No documentation changes for docs.joomla.org needed
• No documentation changes for manual.joomla.org needed

[HLeithner]

This pull request has been automatically rebased to 5.2-dev.

[HLeithner]

I did a code review on all 286 changed files, all of them looking ok except one which is also ok but not changing implizit null

[laoneo]

Thanks!