Cleanup process_group_manager directory

### What

After PR https://github.com/eclipse-score/lifecycle/pull/370 we should organize the directories as the directory names don't respect the abstraction layers.

```bash
score/launch_manager/src/daemon/src/component_manager
├── details
│ └── process // Each implementation of a component has a separate sub folder
│ ├── process.hpp
│ └── process_monitor.hpp
├── icomponent.hpp // All files need to be on the component level
└── run_target.hpp
```

### Acceptance Criteria (DoD)

- All component specific code is in a different directory to all process specific code.

### How

_No response_