BaseTools/Scripts: Add GetUtcDateTime script.

BaseTools/Scripts: Add GetUtcDateTime script.

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=2067

A script that can return UTC date and time in ascii
format which is convenient for patching build time
information in any binary.

Cc: Bob Feng <bob.c.feng@intel.com>
Cc: Liming Gao <liming.gao@intel.com>
Cc: Leif Lindholm <leif.lindholm@linaro.org>
Signed-off-by: Chasel Chiu <chasel.chiu@intel.com>
Reviewed-by: Bob Feng <bob.c.feng@intel.com>
Acked-by: Leif Lindholm <leif.lindholm@linaro.org>