Add blog post providing overview of topology plugin

What does this PR do / why we need it

I have written a blog providing an overview of the Topology plugin explaining its features as well. Added installation and configuration guidelines also.

To-Do Add screenshots

Which issue(s) does this PR fix

Fixes https://github.com/janus-idp/janus-idp.github.io/issues/81

PR acceptance criteria

[ ] Unit Tests
[ ] E2E Tests
[ ] Documentation

janus-idp / janus-idp.github.io

Add blog post providing overview of topology plugin #142

What does this PR do / why we need it

Which issue(s) does this PR fix

PR acceptance criteria

How to test changes / Special notes to the reviewer