[virtualization][wine] Manually run Proton

[LukeShortCloud]

Using the container runtime:

$ gameid=123            # replace with your numeric Steam app ID
$ export STEAM_COMPAT_CLIENT_INSTALL_PATH=$(readlink -f "$HOME/.steam/root")
$ export STEAM_COMPAT_DATA_PATH="/path/to/steamlibrary/compatdata/$gameid"
$ export STEAM_COMPAT_INSTALL_PATH=$(pwd)
$ export STEAM_COMPAT_LIBRARY_PATHS=/path/to/steamlibrary:/path/to/otherlibrary
$ cd /builds/my-game
$ /path/to/steamlibrary/steamapps/common/SteamLinuxRuntime_sniper/run \
    $pressure_vessel_options \
    -- \
    /path/to/steamlibrary/steamapps/common/"Proton - Experimental"/proton \
    run \
    my-game.exe \
    $game_options

https://gitlab.steamos.cloud/steamrt/steam-runtime-tools/-/blob/main/docs/slr-for-game-developers.md#s-r-launch-options