Instead of using multiple parameters in parse_ouput_parameters function
signature, use the struct PGOutputData that encapsulates all pgoutput
options. It will be useful for future work where we need to add other
options in pgoutput.

Author: Euler Taveira
Reviewed-by: Amit Kapila
Discussion: https://postgr.es/m/CADK3HHJ-+9SO7KuRLH=9Wa1rAo60Yreq1GFNkH_kd0=CdaWM+A@mail.gmail.com