feat(http): move HTTP server configuration application, enable flexible duration formats

This commit applies HTTP server configuration in `rootHttpRouterServiceFactory`
and adds support for multiple duration formats for timeouts. The previous
tests for server config have been moved and refactored. The documentation
and CHANGELOG have been updated to reflect the new configuration structure
and supported formats.

Signed-off-by: Beth Griggs <bethanyngriggs@gmail.com>

docs/backend-system/core-services/root-http-router.md

@@ -67,12 +67,18 @@ backend:
     serverShutdownDelay: { seconds: 20 }
   server:
     # (Optional) HTTP server configuration, Node.js defaults apply otherwise
+    # Timeout values support multiple formats:
+    # - Numbers (milliseconds): 30000
+    # - Duration strings: '30s', '1 minute', '2 hours'
+    # - ISO duration strings: 'PT30S', 'PT1M', 'PT2H'
+    # - Duration objects: { seconds: 30 }, { minutes: 1 }, { hours: 2 }
     headersTimeout: 60000
-    keepAliveTimeout: 5000
+    requestTimeout: '30s'
+    keepAliveTimeout: { seconds: 5 }
+    timeout: 'PT30S'
+    # Numeric-only settings
     maxHeadersCount: 2000
     maxRequestsPerSocket: 100
-    requestTimeout: 30000
-    timeout: 30000
 ```
 
 ### Via Code