Add Sip guidelines

# Basic guidelines for formatting a Gulp Sips Series article

## Article Structure
Title
Large Image (replaces 55 words)
Series Description as shown: This is part of our Gulp Sips series: bringing you easily-digestible bits of information on our advanced or unknown features.
Body (can be What?, How?, Why?)

Notes:
* No more than 200 words/2 minute read, including images. This is based on the Medium’s basic time calculations.
* Add a cmd + enter between each titled section
* To add code to Medium
* Block code: add ```before your code
* To add inline code, type your code, highlight it, then click ` (a single tick).

No file or entry point is named. First locate the repository's existing Gulp Sips or article-guidance content, then add the listed structure and Medium formatting rules and verify the resulting guidance covers each requirement.

Written by the indexing model from the issue text.