flatpak: Allow dual installation of app bundles

Part of https://gitlab.gnome.org/GNOME/Initiatives/issues/1.
Allows for the installation of development bundles alongside
stable versions.

Related to https://gitlab.gnome.org/GNOME/gnome-calendar/issues/285

build-aux/flatpak/org.gnome.Calendar.json

@@ -1,5 +1,5 @@
 {
-    "app-id" : "org.gnome.Calendar",
+    "app-id" : "org.gnome.Calendar.Devel",
     "runtime" : "org.gnome.Platform",
     "runtime-version" : "master",
     "sdk" : "org.gnome.Sdk",
@@ -178,7 +178,8 @@
                 }
             ],
             "config-opts" : [
-                "-Dtracing=true"
+                "-Dtracing=true",
+                "-Dprofile=development"
             ]
         }
     ]