[ADF-2463] Moved core components to subfolder (#3062)

docs/core/app-config.service.md

@@ -0,0 +1,100 @@
+---
+Added: v2.0.0
+Status: Active
+---
+# App Config service
+
+Supports app configuration settings, stored server side.
+
+## Details
+
+The `AppConfigService` service provides support for loading and accessing global application configuration settings that you store on the server side in the form of a JSON file.
+
+You may need this service when deploying your ADF-based application to production servers.
+
+There can be more than one server running web apps with different settings, like different addresses for Alfresco Content/Process services.
+
+Or there is a need to change global settings for all the clients.
+
+The service is already pre-configured to look for the "app.config.json" file in the application root address.
+
+That allows deploying ADF-based web applications to multiple servers together with different settings files, for example having development, staging or production environments.
+
+Example of the default settings file content:
+
+**app.config.json**
+
+```json
+{
+    "ecmHost": "http://localhost:3000/ecm",
+    "bpmHost": "http://localhost:3000/bpm",
+    "application": {
+        "name": "Alfresco"
+    }
+}
+```
+
+Please note that settings above are default ones coming with the server. 
+You can override the values in your custom `app.config.json` file if needed. 
+
+You can also change the path or name of the configuration file when importing the CoreModule in your main application.
+
+```ts
+...
+@NgModule({
+    imports: [
+        ...
+        CoreModule.forRoot({
+            appConfigFile: 'app.production.config.json'
+        })
+    ],
+    ...
+}
+export class AppModule { }
+```
+
+Below is a simple example of using the AppConfigService in practice. 
+
+**app.component.ts**
+
+```ts
+import { AppConfigService } from '@alfresco/adf-core';
+
+@Component({...})
+export class AppComponent {
+
+    constructor(appConfig: AppConfigService) {
+
+        // get nested properties by the path
+        console.log(appConfig.get('application.name'));
+
+        // use generics for type safety 
+        let version: number = appConfig.get<number>('version');
+        console.log(version);
+    }
+}
+```
+
+Your custom components can also benefit from the `AppConfigService`,
+you can put an unlimited number of settings and optionally a nested JSON hierarchy.
+
+### Variable substitution in configuration strings
+
+The `AppConfigService` also supports a limited set of variable substitutions to greatly simplify certain scenarios.
+
+```json
+{
+    "ecmHost": "http://{hostname}:{port}/ecm",
+    "bpmHost": "http://{hostname}:{port}/bpm",
+    "application": {
+        "name": "Alfresco"
+    }
+}
+```
+
+The supported variables are:
+
+| Variable name | Runtime value |
+| ------------- | ------------- |
+| hostname | `location.hostname` |
+| port | `location.port` |