Separate python logger module-wise (#2703)

## What do these changes do?
1. Separate the log related code to logger.py from services.py.
2. Allow users to modify logging formatter in `ray start`.

## Related issue number
https://github.com/ray-project/ray/pull/2664

python/ray/test/test_utils.py

@@ -141,7 +141,7 @@ def wait_for_pid_to_exit(pid, timeout=20):
 
 def run_and_get_output(command):
     with tempfile.NamedTemporaryFile() as tmp:
-        p = subprocess.Popen(command, stdout=tmp)
+        p = subprocess.Popen(command, stdout=tmp, stderr=tmp)
         if p.wait() != 0:
             raise RuntimeError("ray start did not terminate properly")
         with open(tmp.name, 'r') as f: