ci: Rework to modern standards

Build x86_64 and aarch64. Rename a few things.

.gitlab-ci.yml

@@ -1,24 +1,33 @@
-include: 'https://gitlab.gnome.org/GNOME/citemplates/raw/master/flatpak/flatpak_ci_initiative.yml'
+include:
+  - project: 'gnome/citemplates'
+    file: 'flatpak/flatpak_ci_initiative.yml'
 
 variables:
+  APP_ID: "org.gnome.Calendar.Devel"
+  BUNDLE: "org.gnome.Calendar.Devel.flatpak"
+  FLATPAK_MODULE: "gnome-calendar"
   GIT_SUBMODULE_STRATEGY: 'normal'
+  MANIFEST_PATH: "build-aux/org.gnome.Calendar.json"
+  RUNTIME_REPO: "https://nightly.gnome.org/gnome-nightly.flatpakrepo"
 
 stages:
-  - 'flatpak'
-  - 'deploy'
+  - build
+  - deploy
 
-flatpak:master:
-    extends: '.flatpak'
-    stage: 'flatpak'
-    variables:
-        MANIFEST_PATH: "build-aux/org.gnome.Calendar.json"
-        RUNTIME_REPO: "https://nightly.gnome.org/gnome-nightly.flatpakrepo"
-        FLATPAK_MODULE: "gnome-calendar"
-        APP_ID: "org.gnome.Calendar.Devel"
-        BUNDLE: "org.gnome.Calendar.Devel.flatpak"
+build-flatpak:
+  extends: '.flatpak@x86_64'
+  stage: build
+  before_script: []
 
+build-flatpak-aarch64:
+  extends: '.flatpak@aarch64'
+  stage: build
+  before_script: []
 
-flatpak:nightly:
-    extends: '.publish_nightly'
-    dependencies:
-        - 'flatpak:master'
+nightly:
+  extends: '.publish_nightly'
+  needs: ['build-flatpak']
+
+nightly-aarch64:
+  extends: '.publish_nightly'
+  needs: ['build-flatpak-aarch64']