Add support for Radio inputs and parameter permitting

[bradgessler]

I believe this is the last use case Superform needs to handle. While it's possible to generate radio inputs via input(type: "radio"), that process is awkward and they won't map back into a collection of values that Rails expects.

I believe this issue was created because of the confusion surrounding the use of radio inputs with Superform: #8

Come up with a few ideas for how syntax should look in this issue, then try implementing it.

Also have a look at how https://github.com/rubymonolith/superform/blob/main/lib/superform/rails.rb#L157 can be changed, if necessary, to support radio style inputs.