Resolve "Ensure Internet Explorer support"

What does this MR do?

The initial idea was to fix whatever issue was making IE unusable but upon further inspection, it was found that even the simple form submission was not supported with IE. Furthermore, the core functionality with Jitsi was also broken, thus this MR now adds a popup that simply tells the user that IE is not supported and they should use a different browser.

Screenshots

after

Does this MR meet the acceptance criteria?

• I have added tests to validate the new functionality.
• I have updated the documentation accordingly.
• I have added translations for all new client-side text.

Closes #172 (closed)