General verify options to openssl ts

This commit adds the general verify options of ocsp, verify,
cms, etc. to the openssl timestamping app as suggested by
Stephen N. Henson in [openssl.org #4287]. The conflicting
"-policy" option of "openssl ts" has been renamed to
"-tspolicy". Documentation and tests have been updated.

CAVE: This will break code, which currently uses the "-policy"
option.

Reviewed-by: Rich Salz <rsalz@openssl.org>
Reviewed-by: Richard Levitte <levitte@openssl.org>