Simplify DPK Readme

[agoyal26]

Suggestions:

1. It should just be pip install dpk - remove unnecessary information about about conda or venv etc
2. On g*_linux-64, then we should say this is only needed for fasttext which is used in transform X. We don't need to expose every corner case to give the quick start example.
3. Suggestion to have notebook setup elsewhere and have the front page just about a runnable main()
4. Make a separate section for installation - It should also describe the difference betweendata-prep-toolkit and data-prep-toolkit-transforms
5. We should add a Terminology section to explain

• pipeline
• transform
• ray
• pure python
• filter
• annotation
• launchers
  @Bytes-Explorer @shahrokhDaijavad @touma-I @daw3rd @santoshborse