[packages] Tidy up configuration

- fix the schema so the schema is valid json-schema
- the schema doesn't actually validate the *operations* yet
- sort the named backends (needs a double-check that the
  list covers all the ones we currently support)

SEE #1441

src/modules/packages/packages.conf

@@ -1,16 +1,18 @@
 ---
 #
 # Which package manager to use, options are:
-#  - packagekit  - PackageKit CLI tool
+#  - apk         - Alpine Linux package manager
-#  - zypp        - Zypp RPM frontend
-#  - yum         - Yum RPM frontend
-#  - dnf         - DNF, the new RPM frontend
-#  - urpmi       - Mandriva package manager
 #  - apt         - APT frontend for DEB and RPM
+#  - dnf         - DNF, the new RPM frontend
+#  - entropy     - Sabayon package manager
+#  - packagekit  - PackageKit CLI tool
 #  - pacman      - Pacman
 #  - portage     - Gentoo package manager
-#  - entropy     - Sabayon package manager
+#  - urpmi       - Mandriva package manager
-#  - apk         = Alpine Linux package manager
+#  - yum         - Yum RPM frontend
+#  - zypp        - Zypp RPM frontend
+#
+# Not actually a package manager, but suitable for testing:
 #  - dummy       - Dummy manager, only logs
 #
 backend: dummy

src/modules/packages/packages.schema.yaml

@@ -4,30 +4,26 @@ $id: https://calamares.io/schemas/packages
 additionalProperties: false
 type: object
 properties:
-    "backend": { type: string, required: true, enum: [packagekit, zypp, yum, dnf, urpmi, apt, pacman, portage, entropy] }
+    backend:
-    "update_db": { type: boolean, default: true }
+        type: string
-    "operations":
+        enum:
-        type: seq
+            - apk
-        sequence:
+            - apt
-            - type: map
+            - dnf
-              mapping:
+            - entropy
-                "install":
+            - packagekit
-                    type: seq
+            - pacman
-                    sequence:
+            - portage
-                        - { type: text }
+            - urpmi
-                "remove":
+            - yum
-                    type: seq
+            - zypp
-                    sequence:
+            - dummy
-                        - { type: text }
+
-                "localInstall":
+    update_db: { type: boolean, default: true }
-                    type: seq
+    update_system: { type: boolean, default: false }
-                    sequence:
+    skip_if_no_internet: { type: boolean, default: false }
-                        - { type: text }
+
-                "try_install":
+    operations:
-                    type: seq
+        type: array
-                    sequence:
+
-                        - { type: text }
+required: [ backend ]
-                "try_remove":
-                    type: seq
-                    sequence:
-                        - { type: text }