REFACTOR: bump to 5.4.0
CLEAN: remove old esp- paks
DEV: Support external esp.json

* Move esp-* paks into catalog
* Remove esp install, uninstall, upgrade and list commands. Now rely on pak
* Remove app.http.content configuration. Now use expansive for this.
* Rename "client" directory to "public" for compatibility with expansive.
* Remove legacy stylesheets() and scripts() abbreviated APIs.
* Rename route vars to uppercase. e.g. CONTROLLERS.