Smack historically provided fine-grained options for the
SSLContext. This is however not flexible enough, as an option to
specifiy the KeyManager(s) was missing.
This deprecated the options for keystore path, keystore type, and
PKCS#11 library, in favor of an option to set the KeyManager, which
could be aware of the keystore path and type, and the PKCS#11
library. At some point, Smack may provide some high-level methods to
create a KeyManager from provided keystore path, keytsore type and
PKCS#11 library.