Enhanced with New Checkpoints, Apple Silicon Support, and Improved Logging

[AravindXD]

Here are the changes/additions that were made:

1. PPO.py : Fixed Indentations and added support for Metal Performance Shaders
2. .gitignore : For making sure unimportant files are not added
3. PPO_preTrained/RocketLanding/PPO_RocketLanding_0_0.pth : Model checkpoint for fine tuning and better usability
4. README.md :
   • updated video for better understanding of usage
   • Dependency guide
   • Apple Silicon support
5. plot_graph.py : Minor fixes and better clarity
6. requirements.txt : project lib requirements
7. test.py :
   • Find and get the latest trained model checkpoint and run tests
   • Confetti celebration for close to perfect landing
8. train.py :
   • Continue training from a checkpoint
   • Cleanups by refactoring/imports from utils.py
9. utils.py :
   • Training Management: Set configurations as per user inputs
   • Checkpoint Management: Finding and loading checkpoints
   • Logging Management: Continue log updating if file exists
   • Plot Management: Plot setup and updating
   • fix: np.mat() --> np.asmatrix() latest version
   • Save Training and logs