Improve documentation for the fullstack crate (#2952)

* improve documentation for the fullstack server context

* Add a section about axum integration to the crate root docs

* make serve_dioxus_application accept the cfg builder directly

* remove unused server_fn module

* improve fullstack config docs

* improve documentation for the server function macro

* fix axum router extension link

* Fix doc tests

* Fix launch builder

* Remove redundant server_only inside server function

* Fix isrg config path

Cargo.lock

@@ -3102,10 +3102,14 @@ dependencies = [
 name = "dioxus_server_macro"
 version = "0.6.0-alpha.2"
 dependencies = [
+ "axum 0.7.5",
+ "dioxus",
  "proc-macro2",
  "quote",
+ "serde",
  "server_fn_macro",
  "syn 2.0.74",
+ "tower-http",
 ]
 
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