Added .build.yml, a Sourcehut builds manifest.

Some current issues:
* Only creates pi4 images right now
* Can report bad images as complete (more a script issue really)
* Current builds are almost too large for unpatched Sourcehut. This is being played with.

.build.yml

@@ -0,0 +1,23 @@
+#shell: true
+artifacts:
+  - /home/build/stormux/build/stormux-pi4.img.xz
+image: archlinux
+packages:
+  - arch-install-scripts
+  - curl
+  - dosfstools
+  - qemu-user-static-bin
+  - wget
+  - parted
+
+sources:
+  - https://gitlab.com/stormux/stormux.git#testing
+
+tasks:
+  - setup: |
+
+      sudo systemctl restart systemd-binfmt
+      cd stormux/build
+      sudo ./build-stormux.sh -n stormux-pi4.img
+      sync
+      sudo xz -9v stormux-pi4.img