Revert "Switch to postgres"

This reverts commit eb518cf5df66ecd45b228bff44411a11396c969d.
Add orderly
Add sorting by Delivery#created_at
Cleanup user roles management

Use promises `.then()` API and the ArrayProxy's `sortAscending` and
`sortProperties`. Delegate loading roles to the controller.
Use DS.Model#one() over #on() with a context
Use `.then()` when loading deliveries
Merge Besko.Date into Date.prototype

Adding in the timezone offset is not working in DST so a more robust
method is needed and should go outside of the constructor.
Move nested delivery routes to top level routes

Will enable properly updating the URL when changing dates on the
deliveries listing page as done with the roles management page.
Use `.route()` over `.resource()`

If only using one route, `.resource()` provides little benefit.
Update URL when navigating deliveries by date
Style sortable column headers