Add algorithm and bits used in key_print2 method and refactor method

Add algorithm and bits used in key_print2 method and refactor method

This adds the the algorithm that is being used. This does not avoid the
empty hmac key output but makes it more obvious, why there is no output.

Master Decrypt (cipher, AES-256-GCM, 256 bits): 705923be f6e44923 a4920a64
434e575c 6ff8d2db d8e74f07 86c010cf 2cf3923e
Master Decrypt (hmac, [null-digest], 0 bits):

Signed-off-by: Arne Schwabe <arne@rfc2549.org>
Acked-by: Gert Doering <gert@greenie.muc.de>
Message-Id: <20221109123501.1252554-1-arne@rfc2549.org>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg25495.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>