Update metadata_advanced.md

[HalfEatenPie]

Is your feature request related to a problem? Please describe.

I'm in the process of trying to connect some coordinate points to basin datasets similar to major_basin_name and minor_basin_name. The metadata_advanced.md seems to be lacking where this dataset is, as I originally checked HydroSHEDS and I can't seem to find the information there either.

I'm happy to run this assessment myself or write the code to extract the data from the base GIS file, but I was wondering where the major_basin_name, minor_basin_name, and aquifier_name are from?

Thank you!

Describe the solution you'd like Name of the GIS data product or service that gives the major_basin_name/minor_basin_name/aquifer_name

Thank you!

[HalfEatenPie]

I may have just resolved my own problem. I think it's from the HydroATLAS dataset from HydroSHEDS. However a confirmation would be greatly appreciated.