Some endpoints not usable within browser

Currently there is the chance to get an 406 error for the devices list for example:

https://sensors.gfz-potsdam.de/backend/api/v1/devices

{"errors":[{"detail":"This endpoint only provides the following content types: application/vnd.api+json, application/signed-exchange;v=b3, application/json, text/html, text/csv","status":"406","title":"Bad request"}],"jsonapi":{"version":"1.0"}}

We should avoid those & allow to browse the API using the browser.