[FEATURE] Added support for TYPO3 13, dropped support for 10 and PHP7

[RinyVT]

Summary

This PR can be summarized in the following changelog entry:

• Added support for TYPO3 13
• Removed support for TYPO3 10 and PHP 7

Test instructions

This PR can be tested by following these steps:

• Clone this branch
• Run ddev start
• Execute ddev install-all to setup the v11, v12 and v13 installations
• Test both the frontend and backend

Quality assurance

• I have tested this code to the best of my abilities
• I have added unittests to verify the code works as intended

Fixes #571

[saitho]

Great to see preparations for TYPO3 v13 have started. :)

As of v13.3.0 TCA fields from ctrl are automatically configured.
The following now causes warnings and errors. I think it's fine to remove those.

// Configuration/TCA/tx_yoastseo_related_focuskeyword.php
        'sys_language_uid' => $GLOBALS['TCA']['tt_content']['columns']['sys_language_uid'],
        'l10n_parent' => array_replace_recursive($GLOBALS['TCA']['tt_content']['columns']['l18n_parent'], [
            'config' => [
                'foreign_table' => 'tx_yoastseo_related_focuskeyword',
                'foreign_table_where' => 'AND tx_yoastseo_related_focuskeyword.pid=###CURRENT_PID### AND tx_yoastseo_related_focuskeyword.sys_language_uid IN (-1,0)',
            ]
        ]),
        'l10n_source' => $GLOBALS['TCA']['tt_content']['columns']['l10n_source'],
        'l10n_diffsource' => $GLOBALS['TCA']['tt_content']['columns']['l18n_diffsource'],
        'hidden' => $GLOBALS['TCA']['tt_content']['columns']['hidden'],

[RinyVT]

@saitho Thanks for letting me know! Code worked in 13.2 but 13.3 had some more surprises so I've done some fixes.
I could net remove the TCA columns because we also support v11 and v12, but I made sure to have a version check around these columns to only add when necessary.