changes:
 - updated fluxio skill struct and to/from ice conversion
 - implemented timeout logic in composite executor
 - get correct timeout value when converting native skill to a fluxio skill

Co-authored-by: Benedikt Engel <uyqhv@students.kit.edu>
Co-authored-by: Julian Tusch <urhrf@student.kit.edu>
Co-authored-by: Peter Albrecht <usnlf@student.kit.edu>

(co-authored: ughlu@student.kit.edu)