Add MainMenu Controller support

[Jannify]

• Make server list controller friendly
• Add delete confirmation for server list
• Make server add window in SN based UI
• Make server add window controller friendly
• Make server join window controller friendly
• Make server password window controller friendly
• Add loading and (error-)message window

Partial-Completes #1653
Closes #1816

[Drakonkinst]

Hi! I'm new here, but I've been reading PRs to get an idea of how this mod is developed. Feel free to take my advice with a grain of salt.

[tornac1234]

Do we want this in for 1.8 ?

[tornac1234]

Currently when we click on a server (to join it) and click on another menu (e.g. Play, Multiplayer) while connecting to the server (first step which is notably long when trying to connect to a server that is not started) there's a loading panel appearing which ends up opening an "unable to connect" panel when failing. But this will still open even if we opened another menu in the meantime. For example if we open options while connecting to a server, when we get the fail message, the menu will try to switch to the multiplayer panel but fail and will leave an empty screen.
A fix for this would to cut connection when exiting the loading tab while connecting to a server.

Also I had some issues while selecting the color picker for some reason, some times it work pretty well, but some times it didn't.

[dartasen]

UI looks better overall

Legend :

• 🔴 Very frustrating
• 🟠 frustrating
• 🟢 Idea

Few suggestions about the UX, leaving that here I don't know how painful is it to do with the code-behind unity API :

• 🔴Unable to scroll with the mousewheel through the server listview when it, I need to hover or focus it with a click on the scrollbar to be able to use the mousewheel scroll
• 🟢 No visual hint that the server has been successfully added to the list using Add Server menu =>
  • Maybe a Log.InGame would do the trick if a proper UI is hard to implement
  • Either add the server at the top of the list or scroll to the entry when it has been added
• 🔴 No warning before clicking on delete on a serve rentry, which is a bit frustrating when using it accidentaly =>
  • A warning popup would do the trick
• 🟠 Didn't look if there's a timeout in our code but in the Loading screen might need a Cancel button if it can be a long process
• 🟠When joining a reachable server, there's no preview of the color we're choosing that we used to have =>
  • Maybe coloring the player name text can be enough if adding back the color rectangle could break the UI
• 🟠 Unable to use tab to switch between entry in server create menu

About the UI :

• 🟢 Maybe we could add some margin in the server listview between items =>
  • The first item is overflowing a bit on the top, you can see if you force the scroll to offset the listview
• 🟢 Add server button looks like a server entry which could be confusing, maybe we could slightly restyle it or move it elsewhere
• 🟢 Unable to connect to server text, ip could be centered