improve ldap query with minimal scope, remove redundant filters; fix deleteUser to really delete pending users

Conflicts:
	projects/cadcAccessControl-Server/src/ca/nrc/cadc/ac/server/ldap/LdapUserDAO.java

Story 1840. Minor change to set the print stream of a command while parsing so that the command is ready after the parser has been instatiated.

Story 1840. Updated approve command based on the new UserPersistence interface. Added unit tests. Refactored some codes.

Story 1840. Added support for all commands. Refactored code to promote code reuse. The commands have not been end-to-end tested because required credentials and ACI's needed to execute these commands (except for --list) are not in place.

Story 1840. Added a method to provide a list of formatted attributes in a String to be used by the ac admin tool.