Add AES support for PIV General Authenticate

This adds algorithm IDs 0xA, 0xA, 0xC which as documented
by the NIST PIV specification is algorithms AES-128, AES-192
and AES-256 respectively.

This patch also addresses some of the hardcodes that prevented
nonces greater than the single byte TLV length tags would allow.
It was explicitly tested with AES-256 and 256 byte nonces.

Signed-off-by: William Roberts <w2.roberts@samsung.com>
But you don't know if the file is a binary key, that happens to end with  0x0a  untill after the is_hex routine is run.