integrate opendj

[subes]

https://github.com/OpenIdentityPlatform/OpenDJ

ApacheDS is slow and not robust against database corruption. OpenDJ might be a better alternative. Integration should behave similarly to ApacheDS.

Embedding example: https://github.com/WrenSecurity/wrends/tree/master/opendj-embedded-server-examples

[subes]

Performance comparison to ApacheDS: https://thehftguy.com/2015/10/05/ldap-benchmark-opendj-vs-openldap-vs-symas-openldap-vs-apacheds/

[subes]

Existing module invesdwin-context-security-ldap-server should be renamed to invesdwin-context-security-ldap-server-apacheds (I guess we will keep it for integrated kerberos server tests, openDJ does not provide a kerberos server) and the new module should be called invesdwin-context-security-ldap-server-opendj