Allow to specify encrypted passwords

[ghenzler]

Usually we use plain text passwords for users - this is not really a problem for test users. For some rare cases it is necessary to specify a password for a non-system, production user (most notably a "replication receiver user" for publish). This should be possible using the same semantics as we have them in JCR: If a password value is enclosed in brackets {encryptedPWStr}, then it should be automatically be decrypted using com.adobe.granite.crypto.CryptoSupport.