Cert: Add enforce_security_policy interface

PySecurity and CertSecurity now provide an API for
calling EnforceSecurityPolicy on the SecurityModule
through the facade

Bug: 145638034
Test: cert/run --host --test_filter=SecurityTest
Tag: #gd-refactor
Change-Id: Ie0ac34b5e2b680d51ce233d646ee53c4f96b2509