Add support for mapping of LDAP groups to ROLES

[sabbyanandan]

As a user, I'd like to configure the mapping of LDAP AD groups against the SCDF roles (VIEW, CREATE, and MANAGE), so I can define the authorization rules in SCDF at the LDAP group level.

See this SO thread for background.

Acceptance:

• I can configure an AD group for example ROLE_APP_MYAPPLICATION_AUTHZ_VIEW against SCDF's ROLE_VIEW role transparently as env-var or properties or in the YAML. Similarly, ROLE_CREATE and ROLE_MANAGE roles can also be mapped to the AD groups
• With LDAP turned-on and the above "group<->role" mapping, I shouldn't have to do anything else. The system interprets the mapping to determine the authorization boundaries automatically
• Shell, APIs, RESTTemplate, and the UI obey the authorization boundaries
• A sample configuration is included in the ref. guide

[ghillert]

Depends on spring-cloud/spring-cloud-common-security-config#7