optimized health status report
remove unnecessary code
extended users mapping and refactored query
use cached query to lookup users by ID

this was already the default in the middleware so should have been
enabled already.

this is properly invalidated on saves.
formatting tweaks
fix "next" url in latest user api

http://manage.dimagi.com/default.asp?110111
refactored query
Merge pull request #3271 from dimagi/user-api-fix

fix "next" url in latest user api
Merge pull request #3268 from dimagi/caching

use cached query to lookup users by ID
Merge pull request #3251 from lwyszomi/109909-case

Optimized health status report
added support for multiple locations per user