Bugfix for registrations in multiple languages

[BUGFIX] Ensure translation handling works as expected #711
[BUG] Subregistration has wrong sys_language_uid #688
[TASK] Better waitlist indication #707
[TASK] Removed deprecated $caseSensitive parameter for like query #703

[DOC] Updated documentation about RSS Feed using Plugin #708

Important notice for TYPO3 9.5.14+ users

If you receive an error message like the shown below, please read on.

Parameter "tx_sfeventmgt_pievent__reguid" for route "tx_sfeventmgt_pievent_0" must match "[0-9]{1..3}" 

Due to changes in TYPO3 Core, the Route Enhancer example from the Documentation were adjusted (especially [0-9]{1..3} has been replaced with \d+). If you use the Route Enhancer example from the documentation, make sure to adjust your configuration.

A working example can be found here: https://docs.typo3.org/p/derhansen/sf_event_mgt/4.2/en-us/ForAdministrators/Configuration/RouteEnhancers/Index.html