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.

Cargo.toml

@@ -17,7 +17,6 @@ members = [
     "packages/liveview",
     "packages/autofmt",
     "packages/rsx",
-    "packages/rsx_interpreter",
     "packages/native-core",
     "packages/native-core-macro",
     "docs/guide",
@@ -42,7 +41,7 @@ rust-version = "1.60.0"
 
 [dev-dependencies]
 dioxus = { path = "./packages/dioxus" }
-dioxus-desktop = { path = "./packages/desktop" }
+dioxus-desktop = { path = "./packages/desktop", features = ["hot-reload"] }
 dioxus-ssr = { path = "./packages/ssr" }
 dioxus-router = { path = "./packages/router" }
 fermi = { path = "./packages/fermi" }
@@ -60,3 +59,8 @@ reqwest = { version = "0.11.9", features = ["json"] }
 fern = { version = "0.6.0", features = ["colored"] }
 thiserror = "1.0.30"
 env_logger = "0.9.0"
+
+[profile.release]
+opt-level = 3
+lto = true
+debug = true