feat: add event to modify a service configuration before creation

[derklaro]

Motivation

There is currently no event that allows to modify a service configuration on the node (via a module) to change the configuration when required. This can for example be setting process parameters or environment variables.

Modification

Add an event (CloudServiceConfigurationPrePrepareEvent) that holds the service configuration and the builder that is used to modify the service configuration in the cloud service factory. The event is called before the final modifications to the configuration are made (ensuring that the service id is only taken once, adding the templates, deployments, ... of the group components etc.). This ensures that no changes are made to the configuration which could potentially break the whole internal service handling.

Result

The configuration of a service can be modified from a (head) node module.

Other context

Resolves #1074