Client-side muting/blocking

[wrdg]

Client can control what users can be seen in their chat window, no messages from blocked users will be visible in the UI but will still be captured in the client logs. Context menu option will be available when right clicking on a user in chat. Manual entry of UIDs to the block list will be available in the settings menu, as well as being able to block from a list of recent chat users (minimizing utility to see if someone is online).