Subtree memorization / reactive templates (#488)

This commit adds subtree memoization to Dioxus.

Subtree memoization is basically a compile-time step that drastically 
reduces the amount of work the diffing engine needs to do at runtime by
extracting non-changing nodes out into a static "template." Templates 
are then understood by the various renderers in the ecosystem as a 
faster way of rendering the same items. 

For example, in the web, templates are simply a set of DOM Nodes created 
once and then cloned later. This is the same pattern frameworks like Lithtml
and SolidJS use to achieve near-perfect performance. 

Subtree memoization adds an additional level of complexity to Dioxus. The RSX
macro needs to be much smarter to identify changing/nonchanging nodes and
generate a mapping between the Template and its runtime counterparts.

This commit represents a working starter point for this work, adding support 
for templates for the web, desktop, liveview, ssr, and native-core renderers.
In the future we will try to shrink code generation, generally improve 
performance, and simplify our implementation.

packages/web/Cargo.toml

@@ -16,7 +16,6 @@ dioxus-html = { path = "../html", version = "^0.2.1", features = ["wasm-bind"] }
 dioxus-interpreter-js = { path = "../interpreter", version = "^0.2.1", features = [
     "web"
 ] }
-dioxus-rsx-interpreter = { path = "../rsx_interpreter", version = "^0.1.0", optional = true }
 
 js-sys = "0.3.56"
 wasm-bindgen = { version = "0.2.79", features = ["enable-interning"] }
@@ -31,7 +30,7 @@ futures-util = "0.3.19"
 smallstr = "0.2.0"
 serde-wasm-bindgen = "0.4.2"
 futures-channel = "0.3.21"
-serde_json = { version = "1.0", optional = true }
+serde_json = { version = "1.0" }
 
 [dependencies.web-sys]
 version = "0.3.56"
@@ -72,12 +71,17 @@ features = [
     "SvgAnimatedString",
     "HtmlOptionElement",
     "IdleDeadline",
+    "WebSocket",
+    "Location",
+    "MessageEvent",
+    "console",
 ]
 
 [features]
 default = ["panic_hook"]
 panic_hook = ["console_error_panic_hook"]
-hot-reload = ["dioxus-rsx-interpreter", "web-sys/WebSocket", "web-sys/Location", "web-sys/MessageEvent", "web-sys/console", "serde_json"]
+hot-reload = ["dioxus/hot-reload"]
+
 
 [dev-dependencies]
 dioxus = { path = "../dioxus" }