SSP-1668 Support case-insensitive usernames

Dependent on https://github.com/dmccallum/person-directory/commit/90a8fb321770513dbec1cc4f96f990ff7ba73235

Essentially applies the config options added by that commit and
copy/pastes some of its code into LocalAccountPersonAttributeDao, which
was already largely a copy/paste of a PD DAO. Also had to make a few
changes to JpaLocalAccountDaoImpl to support the equivalent of
caseInsensitiveDataAttributes in AbstractJdbcPersonAttributeDao.

SSP-Platform will now support case-insensitive uPortal usernames by
default.

This does *not* include any schema migrations to support
case-insensitive db-layer username constraints.