Importing users from CSV into some LDAP directories with password already 'encrypted' is allowed but will never work

After CWD-3294, it's no longer possible to import users from CSV files where the user passwords are already encrypted (hashed) because the directory implementations will throw an InvalidCredentialException when the encrypted password is encountered.

Further up the track, all these users will just be marked as failed to import with no indication to the user why (except for log messages, but there's no indication they should check the logs).

We should check for the directories which require non-encrypted passwords and disallow users from importing with passwords already encrypted into these directories in the CSV importer.

Directories affected: SunOne, Novelle & MS Active Directory (these directories require the passwords to be in plain text when they encode them in their encodePassword() implementation).

This might involve changing the encodePassword() method into a separate set of methods for encoding, encrypting, and checking if the directory supports credential encryption. That which would be nicer than hardcoding a list of directories which don't support credential encryption in the ImportCsv action.