Evaluate merging calls to AD servers #231
Description
Nsls2Api fetches information for some models from BNL's AD server round-robin, addressbook.bnl.gov;
and it fetches information for other models from NSLS-II's AD proxy server round-robin, ldapproxy.nsls2.bnl.gov, which proxies to addressbook. These could/should probably be merged to fetch from a single source of truth, presumably directly from addressbook.
Some changes to ActiveDirectory models might be required, such as an adapter between ActiveDirectoryUser and LDAPUserResponse.
Changes could potentially be upstreamed to N2snUserTools.