API root URL is hardcoded in the client

[mbenadda]

Feature Request

Is your feature request related to a problem or unsupported use case? Please describe. The API url is hardcoded at call sites in Richie (like fetch('/api/v1.0/whatever')). We're probably not going to change this or increment versions any time soon but it's generally cleaner if this is a constant.

Describe the solution you'd like Use a constant, probably set in the settings.

Describe alternatives you've considered N/A

Discovery, Documentation, Adoption, Migration Strategy N/A

Do you want to work on it through a Pull Request? Let's leave this one for a new contributor as a "good first issue"?