prepare for wrap key support

Implemented:
 - array template (file, db, dump file)
 - rfc3394 AES key wrapping (OpenSSL only, Botan code not yet tested)

TODO:
 - test Botan 10 and 11 code (I'll push the commits)
 - rfc5649 (Botan doesn't provide the needed hook yet)
 - of course C_{Wrap,Unwrap}Key code