Docs: Add app architecture for clarity

[noobyco]

Add this application architecture diagram to the /README.md file at the root directory.

Took this arch diagram from https://www.youtube.com/watch?v=b42KAqXUWqY 12:54 { timestamp } --> Open Event Server: Decoupling and Demystifying - Saptak Sengupta - FOSSASIA 2018.

[Gokilp]

please assign to me

[github-actions]

We don't assign issues to external contributors. Please comment that you're working on the issue after checking that no one else is, and then send a pull request for it. Thank You!

[Gokilp]

please assign to me

[github-actions]

We don't assign issues to external contributors. Please comment that you're working on the issue after checking that no one else is, and then send a pull request for it. Thank You!