support for ldap authority in docker set up

[abvaidya]

Enhance current Athenz docker setup with local ldap container. ZMS already support LDAPAuthority.

Expectations -

• modify docker build to add a new container with ldap image
• add necessary set up and deployment scripts to setup ldap server with user accounts which can be used locally
• add documentation to explain the feature and how users can be added in ldap container