BACKLOG-4029 - Ehcache issues when serializing/deserializing LDAP users/groups
https://jira.jahia.org/browse/BACKLOG-4029

Use provider class loader for calls to avoid ClassNotFoundException issues during Ehcache access.
For JCRGroupManagerProvider use a chained class loader of all providers to ensure this also works for cases where for example members or JCR group are LDAP users and LDAP groups.