First Avalonia UI port beta

I've been working on the new version for three straight weeks and I'm kinda burnt out so I'll now slow down a bit while waiting for feedback and bug reports.

I tried improving UI, UX and QoL like with the "one-click-to-play" feature: when you start a server I store almost every setting in a file (Settings/Servers folder) so that, if you click the server button on the same file in the home page, it'll start the server straight away (and CM too if you enabled the option the last time).

I streamlined laps merging and replay exporting where you can now select what players to save depending on their state (left-click: selected, right-click: active, click on the coloured disc: visible/not visible), visible/not visible is also the way to hide cars in the server feature, instead of the old selected/not selected.

I added the green markers to the map, relative to the last selected player, for fine placement when exporting. You can drag the player's car on the map too.

File sized increased a lot because of Avalonia UI libraries and you'll need .NET Framework 10 if not already installed on your PC.

PS: I usually test in dark mode, light mode colors might be a tad off.