[ADF-2973] Angular pipe to get application configuration settings (#3301)

* app config pipe

* update docs

docs/core/app-config.pipe.md

@@ -0,0 +1,40 @@
+---
+Added: v2.4.0
+Status: Active
+---
+
+# App Config Pipe
+
+Retrieves values from the application configuration file directly.
+
+## Examples
+
+```html
+<adf-login
+    copyrightText="{{ 'application.copyright' | adfAppConfig }}">
+</adf-login>
+```
+
+## Fallback values
+
+You can use pipe parameters to pass fallback value:
+
+```html
+<adf-login
+    copyrightText="{{ 'application.copyright' | adfAppConfig:'Fallback Text' }}">
+</adf-login>
+```
+
+## Chaining with other pipes
+
+You can also chain values with other pipes, for example `translation` one:
+
+```html
+<adf-login
+    copyrightText="{{ 'application.copyright' | adfAppConfig | translate }}">
+</adf-login>
+```
+
+## See also
+
+- [App Config service](app-config.service.md)