[FEATURE] Support access to all steps (and the trigger) param values

**Is your feature request related to a problem? Please describe.**
Right now there is no way to access a step, or triggers, params values unless I copy it to an export or return.

**Describe the solution you'd like**
I'd like to be able to do steps.trigger.params.X or steps.stepName.params.X to access a param named X.

**Do you have a workaround?**
Export/return

**Additional context**
Related to #594