Update README.md

[DimsumPanda]

Our README.md isn't super intuitive for someone new to contribute.

1. Change the heading from netlify-website-template to "pyladies-boston-website"
2. Move the Local Development section up.
3. Add in a link to our Boston URL: https://boston.pyladies.com/
4. Link to the CONTRIBUTING.md file

[phenomanaal]

I'm working on this!