Add paging to user management

[danielrbradley]

In case there are a very large number of users, we should page results - perhaps limit to 500 rows just to avoid loading extremely large amounts of data.

[chapmanio]

This has been completed now I believe @danielrbradley?

[danielrbradley]

Nope - only the Cognito based search is currently pages. This issue is to look at introducing paging on all listing APIs in a standard way.

[chapmanio]

A "load more" button has been added, although with sorting this throws up a potential front-end confusion:

#62

Closing this for now, but it can be re-opened if we change how pagination is handled.