New service k5login_generic

- new service k5login_generic (gen, send, slave)
- new attribute module k5loginTargetUser for k5login_generic service
- new method log_msg_without_exit

---------NEED TO BE DONE AFTER MERGE--------------
1] create new attribute resource_def_k5loginTargetUser
2] add rights for attribute k5loginTargetUser
3] create service k5loginTargetUser
4] add required attributes to this service
k5login_generic uses normal krb principals

k5login_generic uses normal kerberos principals instead of admin ones