SecurityPkg: AuthVariableLib: Remove Customized SecureBoot Mode transition.

SecurityPkg: AuthVariableLib: Remove Customized SecureBoot Mode transition.

  Remove Customized SecureBoot Mode transition logic for Mantis 1263, including AuditMode/DeployedMode/PK update management.
  Also remove image verification logic in AuditMode.
The feature has been moved to
  https://github.com/tianocore/edk2-staging/tree/Customized-Secure-Boot
Previous check-in hash is
  SHA-1: 4fc08e8d683522f255727626197d919a40d4836c

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Chao Zhang <chao.b.zhang@intel.com>
Reviewed-by: El-Haj-Mahmoud Samer <samer.el-haj-mahmoud@hpe.com>
Reviewed-by: Fu Siyuan <siyuan.fu@intel.com>