SecurityPkg: enhance secure boot Config Dxe & Time Based AuthVariable.

SecurityPkg: enhance secure boot Config Dxe & Time Based AuthVariable.

V3: code clean up

prohibit Image SHA-1 hash option in SecureBootConfigDxe.
Timebased Auth Variable driver should ensure AuthAlgorithm
is SHA256 before further verification

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Zhang Lubo <lubo.zhang@intel.com>
Cc: Chao Zhang <chao.b.zhang@intel.com>
Cc: Long Qin <qin.long@intel.com>
Cc: Yao Jiewen <jiewen.yao@intel.com>
Reviewed-by: Chao Zhang <chao.b.zhang@intel.com>
Reviewed-by: Long Qin <qin.long@intel.com>