Less clumsy configuration for desktop and mobile (#553)

* chore: dont use prebuilt builder pattern for configuring desktop

* chore: use regular config pattern for web

* Chore: update docs too

* chore: clean up some warnings

packages/router/src/service.rs

@@ -87,11 +87,11 @@ impl RouterCore {
 
         let route = match &cfg.initial_url {
             Some(url) => Arc::new(ParsedRoute {
-                url: Url::from_str(&url).expect(
-                    format!(
+                url: Url::from_str(url).unwrap_or_else(|_|
+                    panic!(
                         "RouterCfg expects a valid initial_url, but got '{}'. Example: '{{scheme}}://{{?authority}}/{{?path}}'",
                         &url
-                    ).as_str()
+                    )
                 ),
                 title: None,
                 serialized_state: None,