Respect multiple languages

[DanielSiepmann]

Currently it's not tested. We have to add necessary tests and adjust the code to respect multiple languages for pages #24 and everything else.
Pages are special as they have a different language handling. Perhaps there is already a way provided by the TYPO3 Core to handle everything the same way.

[DanielSiepmann]

@martinhummer is currently implementing multi language support. The only thing we need to change is to provide the field sys_language_uid to DataProcessors. Currently we remove the field inside TcaTableService.

We should remove this part and put this logic to configuration with RemoveDataProcessor instead and check out his solution.

The language implementation can be found at: https://github.com/martinhummer/search_algolia/blob/master/Classes/Service/RelationResolver.php

As each record has a different uid for each sys_language_uid we currently would index all language versions for each record. By adding sys_language_uid you can filter the records for current active language while searching.

In addition getRecordOverlay and RelationHandler should be used.