Clean up the structure

[pavlenex]

In conversation with @johnsBeharry we agreed that a structure of the repo should be a bit cleaned up to reflect better specific issues we want to tackle.

The re-structure mostly includes folderizing stuff we want segmented.

Johns suggested this:

• User Flows: The Desired Payment Paths/Experiences
• Privacy
• On-chain
• Off-chain
• Consistency On / Off Chain
• Designing for Merchants