Merge GWTC API tools into stock client

steps:

1. incorporate gwtc-specific api commands (https://git.ligo.org/chad-hanna/gwtc/-/blob/main/src/gwtc/gwtc_gracedb.py) into rest.py
2. incorporate gwtc scripts (https://git.ligo.org/chad-hanna/gwtc/-/tree/main/src/gwtc?ref_type=heads) into command-line tool