Feature: Documentation

[unna97]

Is your feature request related to a problem? Please describe.
Need an improved technical documentation. Technical documentation to facilitate not just product usage but also related to contributions.

Describe the solution you'd like

1. README.md : Describe easy installation and setup.
2. Product Documentation: How to use the annotator + the different features available
3. Contributing guidelines and a code of conduct;
4. Code documentation: documentation inside each function (for function definition) & file , API documentation using swagger
5. Project documentation: Documentation on approach chosen & it's reasoning should be included.

Additional context
https://jamesg.blog/category/advent-of-technical-writing/