Inconsistent behaviour for RAM and CPU Monitoring

Describe the bug
The Hardware CPU Module and the RAM Module show inconsistent behavior how the handle child processes.

While RAM uses the Memory of all child process
https://github.com/mlco2/codecarbon/blob/66cc37220f4c2c7b67d0424945d6a13c1b309b23/codecarbon/external/ram.py#L288-L298

CPU Limits itself to the main process https://github.com/mlco2/codecarbon/blob/66cc37220f4c2c7b67d0424945d6a13c1b309b23/codecarbon/external/hardware.py#L247-L253

Expected behavior
Similar behavior for booth, I would be in favor of having "process" and "process_tree" as option

Solution

Adding a "process_tree" option or exchanging the CPU Part with something similar to this:

elif self._tracking_mode == "process_tree":
            # Sum CPU percent for process and its children
            total_cpu_load = self._process.cpu_percent(interval=0.5)
            for child in self._process.children(recursive=True):
                try:
                    total_cpu_load += child.cpu_percent(interval=0.0)
                except (psutil.NoSuchProcess, psutil.AccessDenied):
                    continue
            cpu_load = total_cpu_load / self._cpu_count
            power = self._tdp * cpu_load / 100
            logger.debug(
                f"CPU load {self._tdp} W and {cpu_load * 100:.1f}% => estimation of {power} W for process tree {self._pid}."
            )

Cheers
Dominik

Start by comparing the child-process handling in external/ram.py at lines 288-298 with the CPU logic in external/hardware.py at lines 247-253. Review how tracking modes are represented, then determine whether both modules should support process and process_tree consistently; the work is done when CPU and RAM apply the agreed behavior to child processes.