Implement module layer 2: DataAcquisition

We need to figure out how to place data requests to the esgf archive via thredds/opendap and return the data as an xarray.

Input data:

• opendap_url of the dataset
• relevant time range
• region of interest (maybe thredds only supports bounding box filtering)
• a variable

Output data:

• data set response stored in an xarray structure

Documentation:

• Thredds/Opendap: https://www.unidata.ucar.edu/software/tds/current/tutorial/Subset.html
• ESGF user guide: https://esgf.github.io/esgf-user-support/user_guide.html
• ESGF python doc: https://esgf-pyclient.readthedocs.io/en/latest/