Add a function to getCurrentOsProcess()

Today to get the current OS process, we can do:

```
    OsProcess currentProcess = monitor.processTree().find(monitor.currentPid());
    if (currentProcess != null)
```

The function processTree() reads all process information, on Linux it may be a hundred of files.

As an optimization, we need to add a monitor.getCurrentOsProcess() function who reads only the necessary information.