Meet: Improved error handling
Summary:
- Display error message or any error
- Handler errors when connecting to the OpenVidu session
Test Plan: ./phpunit
Reviewers: #hkccp_developers, mollekopf
Reviewed By: #hkccp_developers, mollekopf
Subscribers: mollekopf, #hkccp_developers
Differential Revision: https://git.kolab.org/D2203