change update_backbone, update_neck, update_head into config.py variables so that the user can choose among the base strat and then select what part of YOLO should not be updated in FL

[co-DE-mon]

I noticed that in FedYOLO\train\strategies.py we are writing update_backbone, update_neck, update_head parameters again and again.
I was thinking why don't we use these parameters only once in FedYOLO\config.py so that we can select the Boolean values once according to the strategy we choose. By doing so we can choose among the basic strat and then separately choose what part of yolo we don't want to be updated in FL

[co-DE-mon]

just a suggestion;)