Client registration interface process

[KlienVo]

• [x] Client gets visual feedback while registering, until registered has happened.
• [ ] display info text (to be set in performance page on server) BEFORE JOINING
• [ ] display info text (to be set in performance page on server) AFTER JOINING/before START
• [ ] isplay info text (to be set in performance page on server) AFTER Start
• [ ] show/hide calibration

When implementing this, also implement #33 by setting a voice corresponding to the chosen language. This might solve #33 but maybe it doesn't.