Move the document trait into a separate crate (#3035)

* add a default head method through eval
* remove the old document trait
* implement document for each platform
* pull out document into a dedicated crate to cut down on shared dependencies
---------

Co-authored-by: Jonathan Kelley <jkelleyrtp@gmail.com>

example-projects/ecommerce-site/src/components/loading.rs

@@ -3,7 +3,7 @@ use dioxus::prelude::*;
 #[component]
 pub(crate) fn ChildrenOrLoading(children: Element) -> Element {
     rsx! {
-        head::Link {
+        document::Link {
             rel: "stylesheet",
             href: asset!("./public/loading.css")
         }

example-projects/ecommerce-site/src/main.rs

@@ -17,7 +17,7 @@ mod api;
 fn main() {
     dioxus::launch(|| {
         rsx! {
-            head::Link {
+            document::Link {
                 rel: "stylesheet",
                 href: asset!("./public/tailwind.css")
             }