draft docs for web modeler api tutorial

[christinaausley]

Description

Drafted docs for Web Modeler API tutorial.

NOTE: In draft as this may change based on final review in camunda/camunda-api-tutorials#5. Will backport once finalized and reviewed.

When should this change go live?

• This is a bug fix, security concern, or something that needs urgent release support.
• This is already available but undocumented and should be released within a week.
• This on a specific schedule and the assignee will coordinate a release with the DevEx team. (apply hold label or convert to draft PR)
• This is part of a scheduled alpha or minor. (apply alpha or minor label)
• There is no urgency with this change and can be released at any time.

PR Checklist

• My changes are for an already released minor and are in /versioned_docs directory.
• My changes are for the next minor and are in /docs directory (aka /next/).

• My changes require an Engineering review, and I've assigned the Engineering DRI or delegate.
• My changes require a technical writer review, and I've assigned @camunda/tech-writers as a reviewer.

[github-actions]

👋 🤖 ✅ Looks like the changes were ported across versions, nice job! 🎉

You can read more about the versioning within our docs in our documentation guidelines.

[pepopowitz]

A few small changes from my end, but this is close!

[christinaausley]

@pepopowitz @akeller I believe this is ready for final review 👍

[akeller]

Thanks for incorporating my feedback!

[pepopowitz]

😍 😍 😍