Send selected language in request header

[rolandgeider]

When sending requests to the server, we should set the Accept-Language. This will make e.g. the error messages that are localized show translated with the rest of the application

TODO: update makeHeader to read the current language and set the headers.

[Nitin2332]

Hi @rolandgeider . I would love to work on this issue. Please assign me this.

[afzal09]

@rolandgeider have a look I have tried to fix this here