Resolve "Prepare callers at home for abrupt cancellations of a call"

What does this MR do?

Add a popup dialog for when family members enter the room so they can be informed about the rules/regulations, emergencies, etc.

Screenshots

before

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 #82 (closed)