Sort hidden users to bottom of user pane, prefix their names with minus sign

[cblgh]

this pr sorts hidden users to the bottom of the user pane (probably dont want someone you've hidden to be in yr face).

their names are also prefixed with a minus sign; eases the amount of mental accounting you need to do to know who is banned & not. see image below for demo

this PR also greatly improves the styling of applied moderation messages, which are virtual messages with type chat/moderation. see image below

[cblgh]

if you have mod, khajit has bans

[okdistribute]

Can someone change their name to something offensive and still be visible? Is there a way to hide banned users completely? (e.g., why not just remove them completely from the pane?)

[cblgh]

@okdistribute yes. the reason is it's a bit complex. one thing i was considering was the following:

• keep the first three letters of the nick, erase the rest and replace with e.g. the first 6 characters of their public key
• stop propagating/acting on user update events in cabal-client from peers that are hidden if (user.isHidden()) return

so fuckedUpTroll becomes fuc-f8a1b4. this still allows identification in case something went wrong, or people are just trying out moderation actions for the first time (don't wanna hide nickwarner and then be unable to reverse the hide!!)

the moderation messages that are forwarded to others also need to maintain the nickname such that people can know who has been hidden by whom, otherwise the moderation system becomes inscrutable see screenshot below

[cblgh]

tracking yr concerns in this issue here #193 @okdistribute, i'll try to add that in a couple of future PRs and focus on first landing the work i already have in the pipeline :)