Added Privacy API patch for GDPR conformity.

[michaelpollak]

Make the Mooduell activity GDPR conform by implementing Moodles Privacy API.

[dasistwas]

Hi @michaelpollak , I think we need to provide export/delete functionality for:

https://github.com/Wunderbyte-GmbH/moodle-mod_mooduell/blob/master/db/install.xml

• table mooduell_games -> player ids (these are userids)
• table mooduell_pushtokens -> userid
• table mooduell_highscores -> userid

Could you have a look at that too? Similar to this: https://github.com/Wunderbyte-GmbH/moodle-local_edusupport/blob/master/classes/privacy/provider.php