Code to produce a notchlist + O3 examples

This is a cleaned up and restructured version of the code to produce the notch list. The original code is located here: https://git.ligo.org/stochastic/stochasticdetchar/-/tree/master/O3/notchlists/make_notchlist

The main file is "pygwb/NotchList_BasisFunctions.py" which defines the necessary basis functions for all the manipulations. These are used in "pygwb/Make_O3_Notchlist.py" to reproduce the O3 notch list and this serves as an example to modify for O4,... The output is in two formats: a human readable and the format that was required by matlab. If desirable the latter format can be changed in case the python code to read the file allows this to increase readability from this type of file.