Support Steam release data layout

[hifi]

No description provided.

[hazelnot]

Commenting here what I said on Discord for ease of access to this info: VC reads the Aftermath data but none of the other main#.mixes. The Counterstrike Missions button is available in the menu, but the submenu itself is empty, and the campaigns fail to load after the first missions with an Unable to read scenario! error.

Console log:

$ ./vanillara
DEBUG: RA95 - Starting up.

INFO : Searching the following paths for path config data:
  argv: '/mnt/WDblack/SteamLibrary/steamapps/common/Command & Conquer Red Alert'
  binary: '/mnt/WDblack/SteamLibrary/steamapps/common/Command & Conquer Red Alert'
  default data: '/mnt/WDblack/SteamLibrary/steamapps/common/share/vanillara'
  default user: '/home/hazelnot/.config/vanilla-conquer/vanillara'
INFO : Read only data directory is set to '/mnt/WDblack/SteamLibrary/steamapps/common/Command & Conquer Red Alert'
INFO : Read/Write user data directory is set to '/mnt/WDblack/SteamLibrary/steamapps/common/Command & Conquer Red Alert'
INFO : Created SDL2 fullscreen window in 0x0
INFO :   pixel format: SDL_PIXELFORMAT_RGB888 (24 bpp)
INFO : SDL2 drivers available: (user preference 'default')
INFO :  opengl
INFO :  opengles2
INFO :  software
INFO : Initialized SDL2 driver 'opengl'
INFO :   flags:
INFO :     SDL_RENDERER_ACCELERATED
INFO :     SDL_RENDERER_TARGETTEXTURE
INFO :   max texture size: 16384x16384
INFO :   8 texture formats supported: (user preference 'SDL_PIXELFORMAT_UNKNOWN')
INFO :     SDL_PIXELFORMAT_ARGB8888 (selected)
INFO :     SDL_PIXELFORMAT_ABGR8888
INFO :     SDL_PIXELFORMAT_RGB888
INFO :     SDL_PIXELFORMAT_BGR888
INFO :     SDL_PIXELFORMAT_YV12
INFO :     SDL_PIXELFORMAT_IYUV
INFO :     SDL_PIXELFORMAT_NV12
INFO :     SDL_PIXELFORMAT_NV21
INFO :   scaler set to 'nearest'
INFO : Found 'allied' disc at: ./MAIN1.MIX
INFO : Found 'soviet' disc at: ./MAIN2.MIX
INFO : Found 'counterstrike' disc at: ./MAIN3.MIX
INFO : Found 'aftermath' disc at: ./MAIN4.MIX
DEBUG: Loaded scenario file
DEBUG: scg01ea.ini
DEBUG: Failed to load scenario file
DEBUG: SCG02EA.INI