[WIP] Contribute Design Guide section

[pavlenex]

This is a WIP.

The goal of this PR is to rename "resources" section into "contribute" that shall provide in-depth tips and concrete examples that should help people better understand how we work and standardize content (hopefully).

I'm following the structure outlined here and the PR is based on discussion here.

Pushing this so people are aware of the issue being tackled and to avoid repetition.

General feedback welcome if you have it though.

To Do (can be do in other PR's)

• Add concrete examples in ContentGuidelines.md
• Add backticks in formatting.md
• Add how to add links in formatting.md
• Create "How to submit.md" as per discussion here
• Re-base the PR entirely and add Contribute section by moving over Formatting and Content Guidelines as per discussion here

[pavlenex]

Blocked by #108
After #108 gets merged I'll re-base the PR, probably create a new one to get rid of way too many overlap.