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

[stack-file]

Adding 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. techstack.yml contains data on all the technologies being used in this repo. techstack.md is a visualization of the YML file and displays the tech stack data in a pretty Markdown file.

💡 Protip: techstack.md contains a comment at the top of the file that the following README snippet (with and without the logos) at the top of the file as a comment:

<--- Readme.md Snippet without images Start --->

Tech Stack

gpupo/common-schema is built on the following main stack:

• PHP – Languages
• DB – Database Tools
• MariaDB – Databases
• PHP-FPM – Background Processing
• GitHub Actions – Continuous Integration
• Travis CI – Continuous Integration
• Shell – Shells

Full tech stack here

<--- Readme.md Snippet without images End --->

Get the code:

## Tech Stack
gpupo/common-schema is built on the following main stack:

- [PHP](http://www.php.net/) – Languages
- [DB](https://github.com/infostreams/db) – Database Tools
- [MariaDB](https://mariadb.com/) – Databases
- [PHP-FPM](http://php-fpm.org/) – Background Processing
- [GitHub Actions](https://github.com/features/actions) – Continuous Integration
- [Travis CI](http://travis-ci.com/) – Continuous Integration
- [Shell](https://en.wikipedia.org/wiki/Shell_script) – Shells

Full tech stack [here](/techstack.md)

---

<--- Readme.md Snippet with images Start --->

Tech Stack

gpupo/common-schema is built on the following main stack:

• PHP – Languages
• DB – Database Tools
• MariaDB – Databases
• PHP-FPM – Background Processing
• GitHub Actions – Continuous Integration
• Travis CI – Continuous Integration
• Shell – Shells

Full tech stack here

<--- Readme.md Snippet with images End --->

Get the code:

## Tech Stack
gpupo/common-schema is built on the following main stack:

- <img width='25' height='25' src='https://img.stackshare.io/service/991/hwUcGZ41_400x400.jpg' alt='PHP'/> [PHP](http://www.php.net/) – Languages
- <img width='25' height='25' src='https://img.stackshare.io/service/11593/no-img.png' alt='DB'/> [DB](https://github.com/infostreams/db) – Database Tools
- <img width='25' height='25' src='https://img.stackshare.io/service/1615/mariadb-logo-400x400.png' alt='MariaDB'/> [MariaDB](https://mariadb.com/) – Databases
- <img width='25' height='25' src='https://img.stackshare.io/no-img-open-source.png' alt='PHP-FPM'/> [PHP-FPM](http://php-fpm.org/) – Background Processing
- <img width='25' height='25' src='https://img.stackshare.io/service/11563/actions.png' alt='GitHub Actions'/> [GitHub Actions](https://github.com/features/actions) – Continuous Integration
- <img width='25' height='25' src='https://img.stackshare.io/service/460/Lu6cGu0z_400x400.png' alt='Travis CI'/> [Travis CI](http://travis-ci.com/) – Continuous Integration
- <img width='25' height='25' src='https://img.stackshare.io/service/4631/default_c2062d40130562bdc836c13dbca02d318205a962.png' alt='Shell'/> [Shell](https://en.wikipedia.org/wiki/Shell_script) – Shells

Full tech stack [here](/techstack.md)