This completes the multilanguage support For this a new setting in the config got added "defaultLanguage"
This currently depends of interacting with matrix_synapse_rest_auth[1] and mxisd[2]. How to integrate that is explained in the README [1] https://github.com/kamax-io/matrix-synapse-rest-auth [2] https://github.com/kamax-io/mxisd