SecurityPkg: UefiSecureBoot: Definitions of cert and payload structures

SecurityPkg: UefiSecureBoot: Definitions of cert and payload structures

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=3910

This change added certificate and payload structures that can be consumed
by SecureBootVariableLib and other Secure Boot related operations.

Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Jian J Wang <jian.j.wang@intel.com>
Cc: Min Xu <min.m.xu@intel.com>
Signed-off-by: Kun Qin <kun.qin@microsoft.com>
Reviewed-by: Jiewen Yao <Jiewen.yao@intel.com>
Acked-by: Michael Kubacki <michael.kubacki@microsoft.com>