Create PR template

[hkirsman]

Always writing the titles from scratch for PR's eg (Description, Screenshots etc) is a bit tedious. Sometimes I might also make a typo or write it differently. Let's create PR template to always have the same base.

From the docs the best one seems creating it in .github folder - out of the way and we could probably add more GitHub related features there.

Based on one previous PR #18 this is the plan:

## Overview



## Screenshots



## Testing