feat(event-gateway): Kong Identity OAuth

[cloudjumpercat]

Description

Fixes #3046

Preview Links

• https://deploy-preview-3374--kongdeveloper.netlify.app/how-to/event-gateway/kong-identity-oauth/

Checklist

• Tested how-to docs. If not, note why here.
• All pages contain metadata.
• Any new docs link to existing docs.
• All autogenerated instructions render correctly (API, decK, Konnect, Kong Manager).
• Style guide (capitalized gateway entities, placeholder URLs) implemented correctly.
• Every page has a description entry in frontmatter.
• Add new pages to the product documentation index (if applicable).

[netlify]

✅ Deploy Preview for kongdeveloper ready!

Name	Link
🔨 Latest commit	9b2bbe2
🔍 Latest deploy log	https://app.netlify.com/projects/kongdeveloper/deploys/69176aa7b1ea840008b1f03b
😎 Deploy Preview	https://deploy-preview-3374--kongdeveloper.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.

---

To edit notification comments on pull requests, go to your Netlify project configuration.

[lahabana]

@cloudjumpercat I've opened a PR to support static tokens on kafkactl: https://github.com/deviceinsight/kafkactl/pull/310/changes

Hopefully it will be accepted and we won't need to use console-producer/consumer for this one guide.