[ENHANCEMENT] Provide a global prefix for the Standalone Camunda application (used in ES/OS)

[ChrisKujawa]

Describe the use case:

When using the (new) Camunda Exporter you can choose as backend between Elasticsearch and Opensearch. The Camunda Exporter will store the data in the respective backends under certain indices, these indices can be prefixed, such that potentially multiple SM installations can be deployed and ES or OS instances can be reused.

Describe the enhancement/feature:

Camunda Exporter (Write) and other components (that read), like Operate, Tasklist and REST API support the definition for an index prefix. Right now there is no single configuration even when using the Standalone Camunda application. This will come with 8.8.

A user would need to configure multiple places to get the prefix usage working correctly. We want to use the Helm charts as the abstraction layer where we can combine all the prefixes under one configuration.

Desired outcome and acceptance tests:

As a user I can define one value, like indexPrefix and this sets the necessary configurations in all places

• Tasklist
• Operate
• ES Exporter
• Optimize
• Camunda Exporter
  * REST API

AT:

• Using the prefix stores the data in indices that contain the prefix in their name. Data is retrievable by the Webapps without issues.

Relates to camunda/camunda#23807