Desmond Vehar

@gpedro @galimru please review

@rgalimov I pushed some changes. I broke out the SlackAction functionality into specific subclasses (`BasicButtonSlackAction`, `InteractiveButtonSlackAction`, `InteractiveSelectSlackAction`) and added tests.

@rgalimov can you please review?

@gpedro please review / merge.

@gpedro just following up. Can this change be merged?

@gpedro @jaypatel512 @rgalimov are you able to merge?