EDU-16571 - Add Weni Events API to Developers Portal

[mariananantua]

Add Weni Events API schema to its own page inside Developers Portal.

This PR is linked to two others:

• Add Weni Events guide to the dev-portal-content repo.
• Update navigation.json in the devportal repo.

Refers to EDU-16571.

Types of changes

• New content (endpoints, descriptions or fields from scratch)
• Improvement (make an endpoint's title or description even better)
• Spelling and grammar accuracy (self-explanatory)

Changelog

Do not forget to update your changes to our Developer Portal's changelog. Did you create a release note?

• Yes, I already created a release note about this change.
• Not yet, but I'm going to.
• No, it's just a fix.

[github-actions]

Thanks for your contribution. The .json file will be checked now with Spectral.