setMuted and closeMeeting methods

[efraespada]

Added implementations of setMuted and closeMeeting for Android and iOS.

Mute or unmute

JitsiMeetWrapper.setMuted(true);

Close the meeting:

JitsiMeetWrapper.closeMeeting();

Tested and working 🚀

I had to modify the jitsi_meet_wrapper_platform_interface dependency to include the new methods.
Please modify this yml after publishing a new version of the platform interface.

dependencies:
  flutter:
    sdk: flutter
  # jitsi_meet_wrapper_platform_interface: ^0.0.3
  jitsi_meet_wrapper_platform_interface:
    path: ../jitsi_meet_wrapper_platform_interface

[saibotma]

Thanks a lot for this PR, and sorry for the delayed response. I have copied it and adjusted some small, mostly naming, things (#56).
It will be released with the next version.