Refactor mass storage to current flipper api (WIP)

applications/external/mass_storage/application.fam

@@ -0,0 +1,13 @@
+App(
+    appid="mass_storage",
+    name="USB Mass Storage",
+    apptype=FlipperAppType.EXTERNAL,
+    entry_point="mass_storage_app",
+    cdefines=["APP_MASS_STORAGE"],
+    requires=["gui"],
+    stack_size=1 * 1024,
+    order=2,
+    # fap_icon="",
+    fap_category="Misc",
+    fap_libs=["assets"],
+)