1. Add support to pegleg to generate a passphrase from CLI
2. Update unit test to ensure encryption/decryption supports passphrase rotation
3. Update order of import statements to satisfy pep8
4. Add unit test for CLI passphrase generation
5. Resolve merge conflicts via rebase
Change-Id: I5cb9e41b2f0fac2451bd2b74f33c48cda417c22d