WithSecureBootPolicyProfile should support user mode

[chrisccoulson]

WithSecureBootPolicyProfile only generates valid profiles on systems that implement UEFI >= 2.5 if deployed mode is enabled. It should support devices that are in user mode as well, as it does already for systems that implement UEFI < 2.5. The pre-install checks I'm working on right now catch this case and disable support for WithSecureBootPolicyProfile, but it should be relaxed to not require that deployed mode is enabled.

If a system is in user mode, the contents of the DeployedMode and AuditMode variables are measured to PCR7.

We may provide an option to make deployed mode a requirement. Note that the UEFI specification only permits platform specific mechanisms to exit deployed mode, so it's possible that enabling it is a non-reversible operation on some hardware.