Main Menu: Server Browser

[vrad-exe]

A new server browser needs to be built in Panorama to replace the old VGUI one. It should include all of the same functionality from the old browser but in a new layout, plus some additions.

This was the layout concept I came up with:

• The top half looks mostly the same, besides the addition of a search bar. The Spectate tab is removed (since I doubt P2CE will be using SourceTV much, if it's even still supported).
• At the bottom you have the action buttons, everything from the right click menu has been moved down here so they can be mapped to controller buttons. The button to create a listen server also exists within the server browser now, making it effectively the top-level multiplayer menu (similar to something like the Overwatch custom game browser).
• The server list columns are the same as the VGUI browser except Bots has been removed, and Game is changed to Game Mode. The string to display here should be set by a serverside cvar.
• Blacklisted servers are now "blocked servers" since blacklist is a somewhat controversial term, and it's easy enough to change. They're also hidden in the filters menu instead of having their own tab, keeping them out of the way.

Clicking the filters button in the search bar opens the filter menu.

• Filters work similar to discord/github search, where there are specific keywords that can be used to narrow down search results, and the filters menu simply acts as shortcuts to these. For example mode:"Deathmatch" would filter to only servers running the deathmatch game mode, or ping:30 would filter to servers with <30ms ping. Ideally these should also support AND/OR/NOT/greater than/less than operators, but I'm not sure how to expose all that in the UI
• The sort dropdown at the bottom is mainly for controller, on keyboard/mouse you can click the column headers to change the sort order (which will also update this dropdown accordingly).
• "Show blocked servers" replaces the blocked tab to keep them further out of the way. When this is enabled the entire server browser would switch to showing blocked servers only (alternatively, maybe this should be a button that opens a submenu?)