- 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/Modules/CustomReactions/Services/CustomReactionsService.cs

@@ -713,7 +713,7 @@ public sealed class CustomReactionsService : IEarlyBehavior, IReadyExecutor
                 {
                     GuildId = guildId,
                     Response = cr.Res,
-                    Reactions = cr.React?.JoinWith("@@@"),
+                    Reactions = cr.React?.Join("@@@"),
                     Trigger = trigger,
                     AllowTarget = cr.At,
                     ContainsAnywhere = cr.Ca,