CIDEVSTC-290 Adds new field to ParameterContext and updates templates

I determined that catalog.xml and datasets.xml were too redundant and removed them. 

The other important bit here is that I'm adding a place in the ParameterContext resource to hold additional metadata that needs to be included in the catalog(s). This can come from user annotations, authored preload parameters or from the uploaded data files for human-in-the-loop QC.

Added new CRUD methods for catalog entries in the external catalog for ERDDAP.