Context:
The following issues have to get fixed in the event ingestion api documentation:

• https://docs.camunda.org/optimize/latest/technical-guide/setup/event-ingestion/#method must include the `/api` path prefix
• https://docs.camunda.org/optimize/latest/technical-guide/setup/event-ingestion/#event-ingestion-api remove `either one by one or ` we only want to document the batch endpoint
• https://docs.camunda.org/optimize/latest/technical-guide/setup/event-ingestion/#request needs to contain the `/api` prefix

AT:

• the changes are reflected on the master branch of the documentation as well as on the `2.7` and `latest` branch