Review and Update API Gateway-related Content in Kyma Learning Journey

[mmitoraj]

Description

Delivering Side-by-Side Extensibility based on SAP BTP, Kyma runtime Kyma Learning Journey got outdated. Markus Haug would like to cooperate with us in updating it.

For the API Gateway module, we need to take care of the following items:

• [Using the API Gateway to Expose Services](https://learning.sap.com/learning-journeys/deliver-side-by-side-extensibility-based-on-sap-btp-kyma-runtime/using-the-api-gateway-to-expose-services_b05bfe98-e216-439d-9fa4-f0ff18f8163b
• Exposing a Service in Kyma with API Rules

Reasons

Content update requiring cross-team collaboration.

Attachments

See #5292 in internal /backlog