Version 11.0.0 not compatible with TYPO3 10.4

[thomas-lepage]

The required version for the core in the latest version of the plugin (11.0.0) says it's compatible with TYPO3 ^10.2 || ^11.5

But there is multiple thing that are not compatible. The first one is the variable declaration in Classes/Database/RteImagesSoftReferenceIndex.php:29

Typed properties are only available in PHP 7.4, but TYPO3 10.4 have a PHP requirement of >= 7.2 <= 7.4. Some installation will not be compatible with the plugin.

Also, in the same classe, it extends TypolinkSoftReferenceParser, but this class is not available in TYPO3 10.4.

All my tests, where made with TYPO3 10.4.21, PHP 7.2 and PHP 7.4