AG0018 - Change to not error on Controller

[dicko2]

If we use this rule on Ctrl then all methods need to be appended with "Async" doesn't make sense

[szaboopeeter]

There is this not-so-much advertised feature since 3.0, which makes makes me think that we might wanna just add Async suffix for async actions: https://docs.microsoft.com/en-us/aspnet/core/migration/22-to-30?view=aspnetcore-3.1&tabs=visual-studio#async-suffix-removal-from-controller-action-names

Edit: though there seems to be some issues with that, like this: https://github.com/dotnet/aspnetcore/issues/14103