Enhanced backup and restore functionality

This commit enhances the backup and restore functionality.  

Enhanced Priam restore functionality includes the following:
- Recognition and handling of  ciphertext.  As part of the restore, Priam will decrypt the ciphertest to plaintext if Fast property (priam.encrypted.backup.enabled) is set to true.  
** Note: for backward compatibility, this Fast property is optional.  Specifically, if it does not exist, no harm done.

- Recognize restore from Google Cloud Storage

- Use AWS Cross Account assumption when restoring from an AWS account.
Follow are the details.

Priam primary backup to AWS supports encryption
- Currently, primary backup to AWS is unencrypted.  This release allows you to specify at a cluster or even instance level, whether the data should be encrypted.  The specification is done via boolean Fast property (priam.encrypted.backup.enabled).  
**Note: for backward compatibility, this Fast property is optional.  Specifically, if it does not exist, no harm done.

Priam uses PGP (Pretty Good Privacy)
For this release Priam will use PGP as the encryption / decryption cryptography algorithm.  Other algorithm can be implemented via interface IFileCryptography and binding your implentation within PriamGuiceModule.java