512731_Add cacheing for static assets (#740)

* 512731_Add cacheing for static assets

* fix: disable static asset caching for local development

Use isProduction config flag to only enable immutable caching
on deployed environments (dev, test, perf-test, prod).

---------

Co-authored-by: Mohammed Khalid <emailmokhld@gmail.com>

Author: nayij

src/server/routes/public.ts

@@ -23,7 +23,7 @@ export default [
   {
     from: '/assets/{path*}',
     to: join(config.get('publicDir'), 'assets'),
-    immutable: false
+    immutable: config.get('isProduction')
   }
 ].map((options) => {
   return {