Create tech stack docs (techstack.yml and techstack.md)

[stack-file]

PR to add tech stack documentation to allow anyone to easily see what is being used in this repo without digging through config files. Two files are being added: techstack.yml and techstack.md. The techstack.yml file contains data on all the tools being used in this repo. The techstack.md file is derived from the YML file and displays the tech stack data in Markdown.

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