laji-api-client person & lang population & http method as method name

[olzraiti]

1. Replaces fetch with methods get(), post(), put(), delete() which make the signature more intuitive to use.
2. Automatically populates lang and personToken into the query params, simplifying client usage and narrowing the surface for bugs.
3. Adds API-Version header to all requests.

[olzraiti]

I moved controlling the personToken & lang to outside the api service (app.component)