SDLOG_ALGORITHM for selecting the crypto algorithm
SDLOG_KEY for selecting the key in keystore to use with the algorithm.
for symmetric algorithms which are currently supported, this is just a free
slot to be used, the key is generated at logging start
SDLOG_EXCH_KEY for selecting an RSA2048 key for encrypting the SDLOG_KEY
Signed-off-by: Jukka Laitinen <jukkax@ssrc.tii.ae>