Modified models to use annotations instead of function calls for most
field validations. Created a few new validation annotations for use
within models.
Per review comments:
- renamed Key to VerifyKey
- enhanced VerifyKey to imply "@Valid", unless disabled
Issue-ID: POLICY-2648
Change-Id: I2b53f218b0a2ab1ed1f5e278816a3509f1408972
Signed-off-by: Jim Hahn <jrh3@att.com>