chore(docs): Add Stripe reference guide

[connorlindsey]

Description

Close issue #20199 by adding reference guide for Stripe. Also updated the doc-links to include the guide under building an e-commerce site.

Related Issues

Closes #20199

[AishaBlake]

Hi, @connorlindsey! Thank you so much for writing this and for your patience while the team was out over the holidays. I have some suggestions and would love to hear your thoughts.

[connorlindsey]

Thanks for all the awesome feedback. I'll make those changes.

[bball07]

I was able to successfully walk through your steps! Thank you

[AishaBlake]

This is looking good! Thanks for contributing this guide and incorporating all that feedback!

[gatsbot]

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