chore: update routing documentation to describe forRoot setup (#2325)

## Related issues

Previous documentation was incomplete:
- the use case where the environment file provides the base href was
missing
- the developer / production context definition was missing

docs/routing/APP_SERVER_ROUTING.md

@@ -2,7 +2,10 @@
 
 In order to get Angular routing redirection to work correctly, you have to correctly provide the ``APP_BASE_HREF`` token from ``@angular/common``. To ease this process, we have created a new routing module to handle this provider together with some useful shell commands.
 
-In your app, you just need to import the ``AppServerRoutingModule`` from ``@o3r/routing``. Example:
+In your app, you just need to import the ``AppServerRoutingModule`` from ``@o3r/routing`` and configure it with your `environment`
+which should be an instance of `@o3r/core` `BuildTimeProperties`.
+
+Example:
 
 ```typescript
 // ...
@@ -11,8 +14,8 @@ import {AppServerRoutingModule} from '@o3r/routing';
 
 @NgModule({
   imports: [
-    // ...
-    AppServerRoutingModule,
+    // ...    
+    AppServerRoutingModule.forRoot(environment),
     // ...
   ],
   // ...
@@ -21,6 +24,7 @@ export class AppModule {}
 ```
 
 By default, the ``APP_BASE_HREF`` will be provided using one of the following items (by priority):
-  * Disabled if it's not the PROD environment
+  * Disabled if it's not the PROD environment (`environment.ENVIRONMENT` === 'prod')
   * the content of ``data-appbasehref`` attribute of ``body``
+  * the value of ``environment.APP_BASE_HREF``
   * the value of ``--app-base-href`` cli option is passed in the build. If the value is not passed, ``APP_BASE_HREF`` will be disabled