[ACS-8706] split context menu to allow injecting actions (#4203)

* ACS-8706 split context menu to allow injecting actions

* ACS-8706 fix class naming, add context menu components unit tests

* ACS-8706 add context menu service, effects and directive unit tests

* ACS-8706 review remarks - redundant condition, directive unit tests

* ACS-8706 improve unit testing approach, remove unnecessary class attributes

* ACS-8706 documentation

* ACS-8706 fix sonar issues

* ACS-8706 replace takeUntil with takeUntilDestroyed

* ACS-8706 fix sonar lint issue

* ACS-8706 change incorrect import path

docs/features/README.md

@@ -26,3 +26,4 @@ This application simplifies the complexity of Content Management and provides co
 - [Search results](/features/search-results)
 - [Search forms](/features/search-forms)
 - [Application Hook](/extending/application-hook)
+- [Context Menu actions](context-menu-actions)

docs/features/context-menu-actions.md

@@ -0,0 +1,69 @@
+---
+Title: Context Menu Actions
+---
+
+# Context Menu Actions
+
+Context Menu Component, appearing on right-clicking a document list item, contains Actions executable on particular file or folder. This entry describes two ways of populating Context Menu.
+
+**Important:** Those two ways are ***mutually exclusive***.
+
+## Default behavior
+
+When using `acaContextActions` directive as shown below, Context Menu actions are loaded from `app.extensions.json` by default.
+
+```html
+<adf-document-list
+    #documentList
+    acaContextActions>
+</adf-document-list>
+```
+
+*Note:* To learn more, see [Extensibility features](../extending/extensibility-features.md) and [Extension format](../extending/extension-format.md).
+
+## Injecting Context Menu Actions
+
+In order to inject custom actions into Context Menu, assign an array of rules, formatted as described in [Extension format](../extending/extension-format.md), to an attribute of a Component using [Document List Component](https://github.com/Alfresco/alfresco-ng2-components/blob/develop/docs/content-services/components/document-list.component.md).
+
+```ts
+const contextMenuAction = [
+  {
+    "id": "custom.action.id",
+    "title": "CUSTOM_ACTION",
+    "order": 1,
+    "icon": "adf:custom-icon",
+    "actions": {
+      "click": "CUSTOM_ACTION"
+    },
+    "rules": {
+      "visible": "show.custom.action"
+    }
+  },
+  {
+    "id": "another.custom.action.id"
+
+    ...
+  }
+]
+
+...
+
+@Component({...})
+export class ComponentWithDocumentList {
+    customContextMenuActions = contextMenuActions;
+    
+    ...
+}
+```
+
+Next, pass them to `customActions` input of `acaContextActions` directive inside component's template.
+
+```html
+<adf-document-list
+    #documentList
+    acaContextActions
+    customActions="customContextMenuActions">
+</adf-document-list>
+```
+
+*Note:* Refer to [Application Actions](../extending/application-actions.md) and [Rules](../extending/rules.md) for information on creating custom *"actions"* and *"rules"* for Context Menu actions.