weather-service: Enable met.no provider
As per the switch to libgweather 40 with commits 216a8984 and a2a6d2e4 we already comply with met.no TOS [1] as we already provide explicitly the application contact info and (implicitly, being a GApplication) the application-id.
So we can enable the met.no weather provider, making the weather forecast to work again.
[1] https://api.met.no/doc/TermsOfService
Fixes: #682 (closed) See also: libgweather#82 (closed)