No docs about using the paid API

[samueleiche]

There is little to no information about authentication, tokens or the "Premium" endpoint.

Our DWG to PDF service stopped working in our app when we found out the /metered url was changed to /unlimited. There is no information about this and we had to write an email for info to get it working again. Soon after it stopped working again, because it seems the new token expired after around 24hrs. The token we had before did not expire in 1-2 years. There is no info about token expiration either.