Directory structure should more closely match information architecture

[jobara]

The directory structure of the documentation should more closely match the information architecture of the deployed site.

The 3 major categories for docs on the website are: Infusion, Tutorials, and Components. The directory structure ideally should mirror this, but currently all documentation reside the same ./src/documents/ directory.

Suggest creation of "Infusion", "Components" and "Tutorials" directories and move relevant documents to them.
Originally from this reported issue: FLUID-6489

Additional context or notes

Originally filed as FLUID-6550 by @jhung on September 14, 2020.