Massive cleanup

- Removed GuildConfigs repository, moved to extensions
- Moved StreamSettings extension to GuildConfig extensions
- namespace NadekoBot.Core has been simplified to NadekoBot in many places (more to come)
- Replaced some raw delete queries with simple linqtodb queries

src/NadekoBot/Modules/Gambling/Common/GamblingConfig.cs

@@ -2,7 +2,7 @@
 using System.Collections.Generic;
 using NadekoBot.Common.Yml;
 
-namespace NadekoBot.Core.Modules.Gambling.Common
+namespace NadekoBot.Modules.Gambling.Common
 {
     public sealed class GamblingConfig
     {