- More code cleanup and codestyle updates

- Fixed some possible nullref exceptions
- Methods signatures now have up to 3 parameters before breakaing down each parameter in a separate line
- Method invocations have the same rule, except the first parameter will be in the same line as the invocation to prevent some ugliness when passing lambas as arguments
- Applied many more codestyles
- Extensions folder fully reformatted

src/NadekoBot/Bot.cs

@@ -70,9 +70,7 @@ public sealed class Bot
     }
 
     public List<ulong> GetCurrentGuildIds()
-    {
-        return Client.Guilds.Select(x => x.Id).ToList();
-    }
+        => Client.Guilds.Select(x => x.Id).ToList();
 
     private void AddServices()
     {