- Migrated to twitch helix api for stream notifications

- Added 2 new fields to creds.yml -> TwitchClientId and TwitchClientSecret
- Users now have to provide them in order to use twitch stream notifications as Twitch is shutting down old api on 18th of February 2022
- Possibly fixed some issues with streams randomly getting cleared
- Added an incomplete trovo stream notification provider

src/NadekoBot/Common/Creds.cs

@@ -72,9 +72,15 @@ Used for cryptocurrency related commands.")]
     public string OsuApiKey { get; set; }
 
     [Comment(@"Optional Trovo client id.
-You should only use this if Trovo notifications stopped working or you're getting ratelimit errors.")]
+You should use this if Trovo stream notifications stopped working or you're getting ratelimit errors.")]
     public string TrovoClientId { get; set; }
 
+    [Comment(@"Obtain by creating an application at https://dev.twitch.tv/console/apps")]
+    public string TwitchClientId { get; set; }
+
+    [Comment(@"Obtain by creating an application at https://dev.twitch.tv/console/apps")]
+    public string TwitchClientSecret { get; set; }
+
     [Comment(@"Command and args which will be used to restart the bot.
 Only used if bot is executed directly (NOT through the coordinator)
 placeholders: 

src/NadekoBot/Common/IBotCredentials.cs

@@ -22,6 +22,8 @@ public interface IBotCredentials
     string CoinmarketcapApiKey { get; }
     string TrovoClientId { get; }
     string CoordinatorUrl { get; set; }
+    string TwitchClientId { get; set; }
+    string TwitchClientSecret { get; set; }
 }
 
 public class RestartConfig