Implement oauth flow for Netatmo WeatherClient instead of requiring all secrets

[calvinmclean]

Description

Instead of generating an access token and refresh token, you should be able to use the oauth flow to redirect to Netatmo website for login. This could be implemented as a CLI helper and/or as part of the process for creating a client using API.

[calvinmclean]

This actually might not work well for my setup because OAuth would make sense for the case where there is a single server shared by multiple users, so the server would own a "Netatmo App" with client ID/secret and this would allow users to grant access to the server by logging-in with OAuth flow.

I should still be able to make it work by allowing POST client ID/secret to create a client, then this will initiate the OAuth flow.