[ACA-1743] extension settings (#1399)

* upgrade tslib

* initial settings skeleton

* migrate language picker setting

* support string parameters

* remove process extensions workaround

* update extensions schema

* update docs

* unit tests

* fix unit test

docs/extending/README.md

@@ -16,6 +16,7 @@ Learn how to extend the features of the Alfresco Content Application.
 - [Actions](/extending/actions)
 - [Application actions](/extending/application-actions)
 - [Rules](/extending/rules)
+- [Settings](/extending/settings)
 - [Application features](/extending/application-features)
 - [Custom icons](/extending/icons)
 - [Registration](/extending/registration)

docs/extending/settings.md

@@ -0,0 +1,45 @@
+---
+Title: Settings
+---
+
+# Settings
+
+The application settings can be accessed via the `/settings` route.
+
+You can project custom configuration groups via the `settings` section:
+
+```json
+{
+  "settings": [
+    {
+      "id": "extensions.ps.settings",
+      "name": "Extensions: Process Services",
+      "parameters": [
+        {
+          "name": "Enable Process Services Extensions",
+          "key": "processServices",
+          "type": "boolean",
+          "value": false
+        }
+      ]
+    }
+  ]
+}
+```
+
+At runtime, you are going to get an extra group called "Extensions: Process Services"
+with a custom boolean setting "Enable Process Services Extensions".
+
+![Custom settings group](../images/aca-settings-custom-group.png)
+
+## Parameters
+
+Each setting parameter object supports the following properties:
+
+| Property | Description                                     |
+| -------- | ----------------------------------------------- |
+| id       | (optional) Unique identifier                    |
+| name     | Public name, can be translation key             |
+| key      | The key to use when saving to the storage       |
+| type     | The type of the value (boolean / string)        |
+| value    | (optional) Default value to use for the setting |