Add AI-powered alpha features management

[akeller]

Description

Introduce process for adding AI feature management to the docs via https://confluence.camunda.com/display/HAN/Accepting+the+Terms+for+AI+Usage+in+Camunda+Console.

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)
• [x] 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

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

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

[akeller]

I wasn't sure if we needed to include a high-level statement on https://docs.camunda.io/docs/reference/alpha-features/ or if the instructions within the Console were enough. Let me know!

Also, if an epic is associated with this work, please add it to the description. There was a bit of confusion around ownership and I can't find an epic that looks like it's related to this topic.