Add description and more documentation for workflows

[monotonik-guy]

What is the feature you'd like to have? Workflow elements in binary ninja for now is not very clear. For example, in workflows there field with description, but I didn't found any descriptions for binary ninja workflow elements. So I can't understand in which moment I need to hook. For example, I had two tasks recently:

1. Catch argument propagation, for fixing creating wrong zmm0/zmm1 args. But Idk what workflow element doing this.
2. Function bounds identifying (for fixing issues where function layout should be fixed). Also, seems it's module level, but what concrete element Idk. So, it would great to have more documentation for each workflow element. Thanks)