Expand bolt-js workflow step creation docs to cover setup on api.slack.com/apps

[filmaj]

Description

The workflow setup documentation in bolt-js does not describe the need to add workflow step(s) to api.slack.com/apps. Without this part, then workflow steps would not show up in Workflow Builder of a workspace.

Related to #1156.

What type of issue is this? (place an x in one of the [ ])

• documentation related

Requirements (place an x in each of the [ ])

• I've read and understood the Contributing guidelines and have done my best effort to follow them.
• I've read and agree to the Code of Conduct.
• I've searched for any related issues and avoided creating a duplicate issue.

[github-actions]

👋 It looks like this issue has been open for 30 days with no activity. We'll mark this as stale for now, and wait 10 days for an update or for further comment before closing this issue out.

[filmaj]

Closing this as workflow steps are deprecated and will be removed at some point this year.