Add PR and issue template in the .github folder

[ananyaarun]

Description

Currently the .github folder of the repo has only a FTO issue template.

Solution

The regular issue template and PR template can be added here like other public lab repositories.
https://github.com/publiclab/plots2/blob/master/.github/ISSUE_TEMPLATE/ISSUE_TEMPLATE.md
https://github.com/publiclab/plots2/blob/master/.github/PULL_REQUEST_TEMPLATE.md

If approved I'd like to add these templates in their respective directories
Thanks!

[welcome]

Thanks for opening your first issue here! Please follow the issue template to help us help you 👍🎉😄
If you have screenshots to share demonstrating the issue, that's really helpful! 📸 You can make a gif too!

[jywarren]

This sounds super! We'd love your help with this! You might look at publiclab/plots2#3681 to get started? Thanks!