Support building AppImage on non-ubuntu systems (#6510)

* Use uname -m instead of uname -p and arch
* Various logging improvements
Co-authored-by: Johannes Lorenz <1042576+JohannesLorenz@users.noreply.github.com>

.github/workflows/build.yml

@@ -50,8 +50,7 @@ jobs:
       - name: Package
         run: |
           cmake --build build --target install
-          cmake --build build --target appimage \
-            || (cat build/appimage.log && false)
+          cmake --build build --target appimage
       - name: Upload artifacts
         uses: actions/upload-artifact@v3
         with: