Enhancements to key import command

Changes to the 'ods-ksmutil key import' command are suggested:

1) When importing add a check that a matching key exists in the hsm (check as many characteristics as possible). If no matching key exists, still do the import but report the details to the user.
2) Add an additional flag '--check-hsm' to the command. If this is used and the check for a matching key fails then the import should fail.