New navigation model (#1)

* Flatten all routing into a single stack

* Replace router with custom implementation

* Add shell header and titles

* Add tab selector

* Add back/forward history menus on longpress

* Fix: don't modify state during render

* Add refresh() to navigation and reroute navigations to the current location to refresh instead of add to history

* Cache screens during navigation to maintain scroll position and improve load-time for renders

src/App.web.tsx

@@ -1,7 +1,7 @@
 import React, {useState, useEffect} from 'react'
 import * as view from './view/index'
 import {RootStoreModel, setupState, RootStoreProvider} from './state'
-import * as Routes from './view/routes'
+import {DesktopWebShell} from './view/shell/desktop-web'
 import Toast from './view/com/util/Toast'
 
 function App() {
@@ -22,7 +22,7 @@ function App() {
 
   return (
     <RootStoreProvider value={rootStore}>
-      <Routes.Root />
+      <DesktopWebShell />
       <Toast.ToastContainer />
     </RootStoreProvider>
   )