docs: add just eat kongverge integration to kong hub

[Gadam8]

NOTE: Please read the CONTRIBUTING.md guidelines before submitting your patch,
and ensure you followed them all:

https://github.com/Kong/docs.konghq.com/blob/master/CONTRIBUTING.md

Summary

A PR to get the Just Eat Kongverge integration into Kong Hub. This includes the addition of a Just Eat publisher directory and a Kongverge extension in the _app/_hub directory. A logo was also added.

Full changelog

• added index.md file for just eat kongverge integration in docs
• added logo for just eat kongverge integration in docs

Issues resolved N/A

Checklist:

• Commit message & atomicity checked
• Documentation
• Spellchecked my updates
• Ready to be merged