LdapImpl/Config: add ignore_case.
PasswordProviders.java: add ignore_case.
SimpleRoleProvider.java: add ignore_case.
Add DBUsernameCaseCheck.java and Spring bean.
AdminImpl.java: inject ignore_case.
LdapImpl.java: check ignore_case in create().
LdapTest.java: update test cases.
AdminImpl.java: fix lookup with ignore_case.
LdapTest.java: fix LDIF, update logic.