Adding steam (prototype)

Dockerfile

@@ -24,6 +24,28 @@ COPY sunshine-entrypoint.sh /etc/sunshine-entrypoint.sh
 RUN sed -i 's/\r$//' /etc/sunshine-entrypoint.sh \
     && chmod 0755 /etc/sunshine-entrypoint.sh
 
+# Steam / Proton
+RUN dpkg --add-architecture i386 \
+    && apt-get update \
+    && apt-get install --no-install-recommends -y \
+        ca-certificates \
+        curl \
+    && curl -fsSL \
+        https://repo.steampowered.com/steam/archive/stable/steam.gpg \
+        -o /usr/share/keyrings/steam.gpg \
+    && printf '%s\n' \
+        'deb [arch=amd64,i386 signed-by=/usr/share/keyrings/steam.gpg] https://repo.steampowered.com/steam/ stable steam' \
+        > /etc/apt/sources.list.d/steam-stable.list \
+    && apt-get update \
+    && apt-get install --no-install-recommends -y \
+        libgl1-mesa-dri:amd64 \
+        libgl1-mesa-dri:i386 \
+        libgl1-mesa-glx:amd64 \
+        libgl1-mesa-glx:i386 \
+        steam-launcher \
+    && apt-get clean \
+    && rm -rf /var/lib/apt/lists/* /var/cache/apt/*
+
 USER 1000:1000
 
 ENV DISPLAY=:20 \