Support for projected volumes at the Mount Trait

### Requirement

I wish I could mount multiple config maps at the same directory. My use case is that I wish I could keep each resource file required by the Integration in its own config file and have all the files mounted at /etc/camel/resources location, regardless of where they came from.

### Problem

Keeping all files in a single config map makes editing a little bit harder, and may reach the 1MB size limit for config maps if the number of files grows.

### Proposal

We could use [projected volumes](https://kubernetes.io/docs/concepts/storage/projected-volumes/) for that;
The operator might detect config maps that are mapped to the same location and automatically use projected volumes to mount them. A configuration would exist to turn on this behavior.

### Open questions

_No response_

Start by reading the Mount Trait implementation and the linked Kubernetes projected-volumes documentation. Identify how config maps mapped to the same directory are represented and where an opt-in configuration could be handled; done means multiple config maps can provide files at one mount location without requiring a single 1 MB-limited config map.

Written by the indexing model from the issue text.