* Be able to make Town Square read-only (Disable typing messages for non admins).
* Do not emit UserTypingEvent when TownSquareIsReadOnly and is Town Square.
* Add unit tests for TownSquareIsReadOnly config value and logic.
* Add TownSquareIsReadOnly to System console>Policy. Added Telemetry.
* Add control for TownSquareIsReadOnly=true only for License Enterprise Edition E10 & E20.
* Update en.json
* Update en.json
* Update policy_settings.jsx
* Change config value from TownSquareIsReadOnly to ExperimentalTownSquareIsReadOnly.
* Refactored to simplify. Avoid code repeat and multiple db calls.