docs: update configuration reference

Author: rezib

docs/modules/conf/examples/gateway.ini

@@ -65,7 +65,9 @@ debug_flags=
 
 [ui]
 
-# Public URL to access the gateway component
+# Public URL to access the gateway component. This is used to setup the
+# frontend application with base URL to gateway endpoints and the base path
+# in pre-built UI assets to replace at runtime the base path placeholder.
 host=https://dashboard.corp.com/
 
 # Serve frontend application with gateway

docs/modules/conf/partials/conf-gateway.adoc

@@ -127,7 +127,10 @@ flags.
 
 |host
 |uri
-|Public URL to access the gateway component
+|Public URL to access the gateway component. This is used to setup the
+frontend application with base URL to gateway endpoints and the base path
+in pre-built UI assets to replace at runtime the base path placeholder.
+
 
 
 *Example:* `https://dashboard.corp.com/`