Refactor train.py and val.py loggers (#4137)

* Update loggers

* Config

* Update val.py

* cleanup

* fix1

* fix2

* fix3 and reformat

* format sweep.py

* Logger() class

* cleanup

* cleanup2

* wandb package import fix

* wandb package import fix2

* txt fix

* fix4

* fix5

* fix6

* drop wandb into utils/loggers

* fix 7

* rename loggers/wandb_logging to loggers/wandb

* Update message

* Update message

* Update message

* cleanup

* Fix x axis bug

* fix rank 0 issue

* cleanup

utils/plots.py

@@ -327,9 +327,8 @@ def plot_labels(labels, names=(), save_dir=Path(''), loggers=None):
     plt.close()
 
     # loggers
-    for k, v in loggers.items() or {}:
-        if k == 'wandb' and v:
-            v.log({"Labels": [v.Image(str(x), caption=x.name) for x in save_dir.glob('*labels*.jpg')]}, commit=False)
+    if loggers:
+        loggers.log_images(save_dir.glob('*labels*.jpg'))
 
 
 def plot_evolution(yaml_file='data/hyp.finetune.yaml'):  # from utils.plots import *; plot_evolution()