Better frontend assets handling and move the react app to /account/ (#1324)

This makes the Vite assets handling better, namely:

 - make it possible to include any vite assets in the templates
 - include the right `<link rel="preload">` tags for assets
 - include Subresource Integrity hashes
 - pre-compress assets and remove on-the-fly compression by the Rust server
 - build the CSS used by templates through Vite

It also moves the React app from /app/ to /account/, and remove some of the old SSR account screens.

crates/cli/src/util.rs

@@ -111,7 +111,12 @@ pub async fn templates_from_config(
     config: &TemplatesConfig,
     url_builder: &UrlBuilder,
 ) -> Result<Templates, TemplateLoadingError> {
-    Templates::load(config.path.clone(), url_builder.clone()).await
+    Templates::load(
+        config.path.clone(),
+        url_builder.clone(),
+        config.assets_manifest.clone(),
+    )
+    .await
 }
 
 #[tracing::instrument(name = "db.connect", skip_all, err(Debug))]