Move to mpk format, add icon for LVGLTest, add more apps to appstore

scripts/bundleapps.sh

@@ -0,0 +1,10 @@
+mkdir -p appstore_backend/bundled_apps
+ls -1 internal_filesystem/apps | while read appdir; do
+    echo "Bundling $appdir"
+    pushd internal_filesystem/apps/"$appdir"
+    # TODO: get and append version from manifest instead of hardcoding:
+    mpkname="../../../appstore_backend/bundled_apps/"$appdir"_0.0.1.mpk"
+    zip -r0 "$mpkname" .
+    cp res/mipmap-mdpi/icon_64x64.png "$mpkname"_icon_64x64.png 
+    popd    
+done