abstract ssh "key" manangement and add support for k5login

added --with-ssh-key-type required arg to remove a key: must identify krb5

remove unneeded script

fixed typo in oo-devel-node per jliggitt

pass comment (key id) into krb5 change methods

fixed arg order in key_entry()
added unit test skeleton
try adding key ids for multiple add/remove
added skeleton kerberos k5login unit tests