Update thredds endpoints to return full path as URL

[roomthily]

To get "actionable" endpoints, we need the full path and we should do this to standardize across the JSON docs. Which mostly means that we need to pass the source URL to the parsers.

[roomthily]

Magic string overlapping fun not with the ID and this is not a step forward in the world. It introduces a kind of ambiguity that is not in the FTP that it is trying to be.

[roomthily]

See 01c2ff6 for the initial untethered url builder.

[roomthily]

The endpoints should get dumped in the right location, JSON-wise, as well - if has_metadata, then pull those to the metadata element vs the dataset endpoints. catalogRef endpoints remain under the servce_description endpoints.

[roomthily]

And need to handle the service base paths based on the access/serviceName attribute if there is one.

[roomthily]

And now for something completely different:

https://rsg.pml.ac.uk/thredds/catalog-cci.xml?dataset=CCI_ALL-v1.0-MONTHLY

which returns the catalog.xml (can't ask for catalog.xml) but with query parameters and no way of knowing that.