CI: Improve the flatpak review environments

For more:
https://gitlab.gnome.org/GNOME/Initiatives/wikis/DevOps-with-Flatpak#flatpak-bundle-for-every-mr-and-commit

.gitlab-ci.yml

@@ -3,6 +3,7 @@ stages:
   - build
   - test
   - manual
+  - review
   - deploy
 
 .Log files: &log_files  [./*.log, _build/meson-logs/]
@@ -144,12 +145,13 @@ pages:
 # Creates a flatpak
 ##
 flatpak:
-  stage: deploy
+  stage: manual
   image: registry.gitlab.gnome.org/gnome/gnome-runtime-images/gnome:master
   artifacts:
     name: package
     paths:
     - $(pwd)/*.flatpak
+    expire_in: 2 days
 
   variables:
     APPID: "org.gnome.SettingsDevel"
@@ -187,11 +189,43 @@ flatpak:
   cache:
     paths:
     - .flatpak-builder/cache
+  when: manual
+  except:
+    - tags
+    - gnome-3-.*
+    - master@GNOME/project-url
 
+review:
+  stage: review
+  dependencies:
+    - flatpak
+
+  when: manual
+  variables:
+    BUNDLE: "org.gnome.SettingsDevel.flatpak"
+  script:
+    - echo "Generating flatpak deployment"
+  artifacts:
+    paths:
+        - ${BUNDLE}
+    expire_in: 30 days
   environment:
     name: review/$CI_COMMIT_REF_NAME
     url: https://gitlab.gnome.org/$CI_PROJECT_PATH/-/jobs/$CI_JOB_ID/artifacts/raw/${BUNDLE}
+    on_stop: stop_review
+  except:
+    - tags
+    - gnome-3-.*
+    - master@GNOME/project-url
+
+stop_review:
+  stage: review
+  script:
+    - echo "Stopping flatpak deployment"
   when: manual
+  environment:
+    name: review/$CI_COMMIT_REF_NAME
+    action: stop
 
 # Runs the sanitizers [address, thread, undefined, and memory].
 .sanitizer: &sanitizer