Improve formatting of the query JSON results in the web interface

[trevorhardy]

Describe the solution you'd like Currently the web interface queries return a block of text (generally JSON but not always, see https://github.com/GMLC-TDC/HELICS/issues/1746). Once all the queries are returning JSON, we should pretty-print.

Long-term we should think about which of the data fields in each JSON need to be presented to users to minimize the visual clutter.