Simplify template by removing custom handler

[thheller]

The template (shadow-cljs variant) generates a src/user.clj with a custom handler. The only purpose of this handler seems to be to serve classpath resources from the public prefix. This can be done purely via shadow-cljs.edn :dev-http config and does not need a custom handler.

Just turn

{...
 :dev-http     {3000 {:root    "public"
                      :handler user/app}}}

into

{...
 :dev-http     {3000 ["public" "classpath:public"]}}

as mentioned in the docs.

[yogthos]

Yeah that sounds reasonable to me, any chance you could do a pr with the update? :)