vkQuake2 1.5.3

• added support for MOUSE4 and MOUSE5 buttons on Windows
• added vk_fullscreen_exclusive command and a proper video menu setting to enable/disable exclusive fullscreen mode on Windows
• added debug_console cvar to enable/disable debug cmd console on Windows
• fixed push constants related validation errors detected by latest validation layers
• MSAA color buffer is now created only when it's actually needed
• the game is now trying to use triple buffering instead of double buffering, if available
• the vk_strings command now prints swapchain image count currently in use
• fixed the "missing maps/ntro.inn.bsp" error that occurs on some Linux distributions
• crosshair is now properly centered on the screen
• crosshair images are now stored in a separate scrap texture with S_NEAREST filtering - this fixes display issues for the dot crosshair and makes it look more consistent across different values of hudscale cvar.