Rebuild samples

Updates!

* hello-world, server-with-links, ring-middleware were straightforward.
* template server pages now produce identical html and have been updated to recent versions
* cors sample was completely overhauled.

With the exception of `hello-world`, changed all of the `main` functions to follow this structure:

```clojure
(-> service/service
    server/create-server
    server/start))
````

Other stuff:

* Removed `dev` clutter; we should consider adding a sample focused around actual development 
work processes, but with dev scattered about, each sample loses focus.
* Moved source files, templates, static files, etc. into `resources/` directories.
* Updated documentation where required.