Feature request thread for supporting new model data sources

[tsjackson-noaa]

This is a thread for requests for the package to support running diagnostics on model data from different "sources" beyond what's currently supported. By "data source" we mean a set of functionality for obtaining requested data from a remote provider:

• Interfaces to query the remote store of data for the variables requested by the PODs, whether in the form of an organized data catalog/database or in file naming conventions;

• (Optional) heuristics for refining the query results in order to guarantee that all data selected came from the same experiment;
• The data transfer protocol to use for transferring the selected data to a local filesystem to be analyzed by the PODs.

Our initial development has focused on data on locally mounted filesystems, specifically the project's own sample model data and the CMIP6 Data Reference Syntax, primarily because these were the most in-demand cases. The MDTF package is developed as a community effort, and we need community input to prioritize how we should allocate developer resources.

Community contributions are even better -- if you've adapted the framework to use data from a new source, please submit a pull request!