CAS-1253 Avoid duplicate joda-time dependencies.

Duplicate joda-time dependencies may arise in overlays that include cas-server-support-ldap. Declare direct depencency on joda-time for core and cas-server-support-ldap and exclude from transitive dependencies to ensure single consistent version.
(cherry picked from commit ce6d842cae893a6e9ae9aaef06e319a530c474ab)