Add commit guide to CONTRIBUTING.md

[ithinkandicode]

With a reference link for contributors to better understand conventional commits, and the commit emojis.

And a table for quick copy + paste for commit prefixes.

Here's all the emojis I could find in the PRs.

Please edit this text if you know what these are for.

Type	Prefix	Notes
Feature	feat: ✨	Added new feature(s)
Refactor	refactor: ♻️	Reworked existing code to be better (eg. for clarity/performance)
Refactor	refactor: 🚚	Move files / code (eg #255)
Bugfix	fix: 🐛	Fixed an error in the code
Bugfix	fix: ✏️	Fixed a typo
Style	style: 🎨	Improve the code style of the code
Style	style: 🏷️	Added / Updated types
Docs	docs: 📝	Related to writing docs (eg #279)
Tests	test: ✅	Add / Update tests
Build	build: 🔥	Changes that affect the build system or external dependencies - The 🔥stands for removing code or files, so in this case, a file or code related to the build system was removed.
CI	ci:	Related to continuous integration (CI)
Chore	chore:	Other changes that don't modify src or test files
Chore	chore: ⬆️	Update a version number

[KANAjetzt]

We've decided not to add the emojis to the guidelines, but we should add a section about conventional commits and the squash and merge workflow on the dev branch.