Move encrypt room option to Security page

Encrypt room is not a frequency used option, display them on the drawer can took some place that can be used to display other useful status, and this option is not a regular option that can be turned off so we should also avoid it get triggered that easy for desktop user.

This patch moves the option to Security page like what Element did, and adds a description to tell the user it cannot be disabled before clicking it.

This patch also adds a badge icon to the drawer room avatar to indicate if a room is encrypted.