add multi-value settings, handle visibility levels & import sources

Make `apply-settings` send JSON in the request body, which enables us to
set values that take an array.

Use that to handle restricted_visibility_levels and import_sources.

This commit reflects the current state of production settings.

Bug: T284336

gitlab-settings/apply-settings

@@ -93,7 +93,7 @@ if confirm('Does the diff look good?'):
                 local_settings[x] = 'false'
 
         try:
-            r = requests.put(url, headers=headers, data=local_settings)
+            r = requests.put(url, headers=headers, json=local_settings)
             r.raise_for_status()
             new_instance_settings = r.json()
         except:

gitlab-settings/settings.yaml

@@ -3,17 +3,11 @@
 # True / false values here should be booleans - necessary type juggling to turn
 # these into strings for the API is handled in the script.
 #
-# TODO:
-#
-#   - Enable import from Phabricator: Admin Area, Settings, General, Visibility
-#     and access controls, Import sources: enable Phabricator
-#   - import_sources: 'github,bitbucket,bitbucket_server,gitlab,google_code,fogbugz,git,gitlab_project,gitea,manifest,phabricator'
-#   - Configure visibility levels: "restricted_visibility_levels": [ "private" ]
-
 # Settings not modeled here:
 #
-# - Accept Let's Encrypt ToS: Admin Area, Settings, Preferences, Pages, I have
-#   read and agree to the Let's Encrypt Terms of Service: checked
+#   - Accept Let's Encrypt ToS: Admin Area, Settings, Preferences, Pages, I have
+#     read and agree to the Let's Encrypt Terms of Service: checked
+
 # Disable public sign up: Admin Area, Settings, General, Sign-up restrictions,
 # Sign-up enabled: unchecked
 signup_enabled: false
@@ -97,4 +91,22 @@ gravatar_enabled: false
 # experience than being immediately sent to a login form:
 home_page_url: "https://gitlab.wikimedia.org/explore"
 
-
+# Restrict available visibility levels for new projection creation to public:
+restricted_visibility_levels:
+  - internal
+  - private
+
+# List of accepted import sources: Admin Area, Settings, General, Visibility
+# and access controls, Import sources:
+import_sources:
+  - github
+  - bitbucket
+  - bitbucket_server
+  - gitlab
+  - google_code
+  - fogbugz
+  - git
+  - gitlab_project
+  - gitea
+  - manifest
+  - phabricator