Remove the success field from responses

[mjs]

This field is redundant and less meaningful than the HTTP status code.

This can't be done until the Cacophonometer app stops relying on this field

[mjs]

See https://tree.taiga.io/project/the-cacophony-project/us/361?kanban-status=268959

[jackodsteel]

Removal from Cacophonometer included in this PR:
https://github.com/TheCacophonyProject/cacophonometer/pull/42

[jackodsteel]

Note still needs to be removed from the web UI:
TheCacophonyProject/cacophony-browse#14

[mjs]

Very cool to see this moving forward. We can't remove it from the API server until we're sure that all cacophonometers have been upgraded to a sufficiently new version. There are also some other clients (e.g. the cptv-download.py) which may need to be adjusted.