scd:piv: Support rsa3072
* scd/app-piv.c (PIV_ALGORITHM_RSA): Rename to PIV_ALGORITHM_RSA_2048. (PIV_ALGORITHM_RSA_3072): New. (get_key_algorithm_by_dobj): Decide whether to use 3072 or 2048. (do_sign): Support rsa3072. (do_decipher): Ditto. (do_genkey): Ditto.
Take care: Due to a lack of a PIV token capable of 3072, this has
not been tested at all.