Rename expected parameters on backend to match front end.

[psdcode]

Currently there is a mismatch between frontend and backend for several parameters, so front-end changes these parameters before sending an api call. It would be more straight forward to simply change what the backend can accept:

• Backend expects municipality param, but in the front-end we use and display city param in the address bar.
• For the doctype param, when its value is organization in the front-end, the corresponding value in the backend is entity

Alternatively, the backend could accept both the current and suggested above params

[psdcode]

@brittwitham I assigned you for this issue, but if you think this will take more than 5 minutes and cannot be included in one the other two backend related recent issues' PRs, feel free to ignore it. It's a quality of life improvement for the frontend, but not critical.