[dice] Move DiceGenerateCertificate nostd/std versions to diced_open_dice

As a step of merging the existing diced_open_dice_cbor library into
the new open-dice wrapper diced_open_dice.

Bug: 267575445
Test: atest diced_utils_test diced_sample_inputs_test \
diced_vendor_test diced_open_dice_cbor_test \
libdiced_open_dice_nostd.integration_test \
libdiced_open_dice.integration_test diced_open_dice_cbor_test

Change-Id: Id50648f12be6cb236e8ea268bbbe791a30d5269b
4 files changed