Salts and Passphrases are both strings used in cryptography. This patch:
1. Adds CLI generation of salt
2. Adds unit test for CLI generation of salt
3. Updates passphrase.py code to be more generic as it is used to generate
both a passphrase and a salt
4. Update name of passphrase.py to be more generic
5. Update all references to, and tests of passphrase.py
6. Add documentation for CLI generation of salt
Co-Authored-By: chittibabu <cg329x@att.com>
Change-Id: I71858d63a2846290d22be96686ccfea3ba8aa6c0
671b77f6a7