Quick Fix for #167

[TheAxelander]

Extend CredentialManager to accept refresh_token and add warning message for deprecated GenerateToken

Example usage:

var clientId = "myClientId";
var clientSecret = "myClientSecret";
var accessToken = "myAccessToken";
var refreshToken = "myRefreshToken";

var client = new Client(
    SystemClock.Instance, "https://api.netatmo.com/",
    clientId,
    clientSecret);

client.ProvideOAuth2Token(accessToken, refreshToken);
await client.RefreshToken();
var stationsData = await client.Weather.GetStationsData();

[TheAxelander]

I wrote a small test script to see if it works, below was the output:

Manually provide initial AccessToken & RefreshToken:

AccessToken: ##############
RefreshToken: ##############
ExpiresAt: 2023-07-17T07:23:00Z
ReceivedAt: 2023-07-17T07:22:40Z
**********************************

Request Refresh Token:

AccessToken: ##############
RefreshToken: ##############
ExpiresAt: 2023-07-17T10:22:41Z
ReceivedAt: 2023-07-17T07:22:41Z
**********************************

Livingroom Temperature: 24,2
Office Temperature: 24,8
Outdoor Temperature: 19,6

During init of a Client the token is valid for 20 seconds. After calling RefreshToken() the token gets a validity from the API with 3 hours. I was also able to get my data from Netatmo API.

[Riges]

It will fix #167, I will validate and publish it's.