Rearrange chapters and update table of contents

[dhruvbalwada]

No description provided.

[LaureZanna]

👍

[dhruvbalwada]

@LaureZanna could you approve this? This would mean :

• going to the tab at the top of this PR that says "files changed"
• clicking the button "review changes"
• select "Approve" and submit.

[LaureZanna]

@dhruvbalwada : I really like the new structure!! I am wondering if we should think at the end how to modify some of the titles to make them a little more uniform.

[dhruvbalwada]

Yes, definitely will rename and beautify close to end. For now I mostly wanted to test if rearranging and naming works. Was trying to follow formatting similar to: https://physicsbaseddeeplearning.org/diffphys.html