Move api/ to rest/
Move configuration out of configure.js

 - Reduce REST API related settings to two properties:
   `restApiRoot` and `restApiUrl`.

 - Move `web/` config to `web/app.json` and `web/app.local.js`.

 - Refactor `rest/` and `web/` so that `rest/` exports only the REST API
   endpoint. Move loopback-explorer setup to the `web/` component.
Remove unused file html5/utf8
Move configuration of routes out of configure

Create a new file `html5/config.routes.json` to keep the list of known
routes.