DOC - Moving Tips and Trick from wiki to Style Guide - added Reading …
This changes referring to https://github.com/pandas-dev/pandas/issues/30964 is for removing tips and tricks section page from the [wiki](https://github.com/pandas-dev/pandas/wiki/Tips-&-Tricks-for-pandas-dev) to the [Code Style guide](https://pandas.io/docs/development/code_style.html). 

Since this is my first contribution, I've tried to keep this as simple as possible. @simonjayhawkins mentioned that the conventions for urlopen and ZipFile should be captured under our contributing style guide, testing section. I've seen that there is no Testing section and have created a new section and added these two sections from the Wiki post here. Enabling the Travis-CI and Azure CI pipeline build seemed a bit tough for me. I will try to do the build from my side in my next PR. 

Let me know if any corrections are needed.

