BaseTools/Capsule: Support signtool input subject name to sign capsule file

BaseTools/Capsule: Support signtool input subject name to sign capsule file

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=3928

Windows-based system using signtool.exe to sign the capsule.
Add the support to using "--subject-name" argument to assign
the subject name used to sign the capsule file.
This argument would pass to signtool.exe as a part of input
argument with "/n" flag.

NOTE: If using signtool.exe to sign capsule at least need to
      choose one of "--pfx-file" and "--subject-name"
      argument to input the value.

Signed-off-by: Jason1 Lin <jason1.lin@intel.com>
Cc: Bob Feng <bob.c.feng@intel.com>
Cc: Liming Gao <gaoliming@byosoft.com.cn>
Cc: Yuwei Chen <yuwei.chen@intel.com>
Cc: Michael D Kinney <michael.d.kinney@intel.com>
Cc: Dakota Chiang <dakota.chiang@intel.com>
Reviewed-by: Liming Gao <gaoliming@byosoft.com.cn>
Reviewed-by: Bob Feng <bob.c.feng@intel.com>