SSP-2473 Backport platform person lookup by schoolId

Essentially a cherry-pick of the non-SsoController portions of
df33770a7c3429b59ff2aeb2892c52d6d0b47e16 (SSP-2289 and others).

In order for this to actually work, we also need
ad015f9f8ff1424e3cbd8ae6ce1cab2078c43070, but it's just slightly
simpler to keep the commits separate, so that's what I'm doing.
SSP-2452 Specify username data attr name in uPortalJdbcUserSource
SSP-2466, SSP-2289 Pass through unmapped attr queries to local uP DAO

This fixes a regression created by
df33770a7c3429b59ff2aeb2892c52d6d0b47e16 (SSP-2289), which in an
attempt to respect logical->physical attr mappings when querying the
local uP PD DAO, unmapped attr queries were effectively swallowed.
This restores the previous behavior which handled such queries by
using the logical attr name in the client's query as the physical
attr name in the actual db query.