SSP-2289 Add support for sectionCode and studentUserName SSO params
SSP-2289 Add support for termCode SSO params
SSP-2289, SSP-2422, SSP-2425 Support schoolId in SSO requests

Expands on previous SSP-2289 work to add support for schoolId
as a param to identify the SSO-ing end user. Along the way it
also corrects error response status codes (SSP-2425) and
requires that the SSO-ing end user be resolvable as such
(SSP-2422).

Note that the schoolId support involved some fairly significant,
if small in terms of LoC, changes to core uP/SSP-Platform
user attribute handling. In particular, the default local
attribute mapping in personDirectoryContext.xml changed to
explicitly map 'schoolId' as a queryable logical attribute,
pointed at the 'username' physical attribute by default. I.e.
the queryAttributeMapping config now more closely matches the
resultAttributeMapping config. We had to do this for schoolId
because it doesn't actually have its own physical attribute.
So previously uP would happily query on it for us, but would
never find any results. Once we changed the queryAttributeMapping,
though (<entry key="schoolId" value="username" />), the lookups
still didn't work for two reasons:

  1) LocalAccountPersonAttributeDao wasn't mapping logical
     attribute names to physical attribute names like we expect
     in "standard" PersonDirectory DAOs, so 'studentId' was being
     passed through to the db literally as the attribute name, and:

  2) Once the code was added to actually respect the logical->physical
     mapping query attribute mapping, it still didn't work because
     'username' is modeled differently and has so be called out
     specially to the underlying DAO (JpaLocalAccountDaoImpl).