feat: Runner image variants, CI improvements

- Added easily doable variants for runners, with simple CI build matrix.
- Added playsite in CI builds finally.
- Some CI formatting and naming fixes.

containerfiles/heroic-runner.Containerfile

@@ -0,0 +1,23 @@
+# Container build arguments #
+ARG RUNNER_COMMON_IMAGE=runner-common:latest
+
+#*********************#
+# Final Runtime Stage #
+#*********************#
+FROM ${RUNNER_COMMON_IMAGE}
+
+### FLAVOR/VARIANT CONFIGURATION ###
+## HEROIC LAUNCHER ##
+RUN --mount=type=cache,target=/var/cache/pacman/pkg \
+    pacman -S --noconfirm heroic-games-launcher-bin && \
+    # Cleanup
+    paccache -rk1 && \
+    rm -rf /usr/share/{info,man,doc}/*
+
+## FLAVOR/VARIANT LAUNCH COMMAND ##
+ENV NESTRI_LAUNCH_CMD="heroic"
+### END OF FLAVOR/VARIANT CONFIGURATION ###
+
+### REQUIRED DEFAULT ENTRYPOINT FOR FLAVOR/VARIANT ###
+USER root
+ENTRYPOINT ["supervisord", "-c", "/etc/nestri/supervisord.conf"]