UserAuthFeaturePkg/UserAuthenticationSmm: Support Standalone MM.

[xuweiintel]

Refactor UserAuthenticationSmm to support Standalone MM.

• Factor out variable lock code logic that references boot services.
• UserAuthenticationStandaloneMmDxe is added to lock the variables. It is only used for UserAuthenticationStandaloneMm.
• UserAuthenticationStandaloneMm doesn't lock the variables, needs to rely on UserAuthenticationStandaloneMmDxe to do the lock.
• UserAuthenticationSmm still locks the variables by itself, no need to include UserAuthenticationStandaloneMmDxe.
• Register gEfiEventExitBootServicesGuid notify which is used by the StandaloneMmCore.

Since gEdkiiVariableLockProtocolGuid is a deprecated interface, use gEdkiiVariablePolicyProtocolGuid to lock password variables instead.

Cc: Dandan Bi [email protected] Cc: Nate DeSimone [email protected] Cc: Liming Gao [email protected]