Add architecture markdown file to docs

[arjunsridhar12345]

Interested in adding an architecture markdown file that includes a detailed file on how the current repo aligns with the low level diagram, examples on how to contribute, some takeaways, and a change log as well.

I think this can serve multiple use cases - architecture, examples, retrospect, etc.

[arjunsridhar12345]

will also help in updating low level diagram as well