README update

[romanc]

Description

I noticed we had a "TBD" section for contributions / coding guidelines and i thought this is the perfect place to document squash merge for pull requests. Couple more changes followed from there. Nothing really new, just re-ordered some things.

How Has This Been Tested?

By doing a self-review.

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas: N/A
• I have made corresponding changes to the documentation
• My changes generate no new warnings: N/A
• Any dependent changes have been merged and published in downstream modules: N/A
• New check tests, if applicable, are included: N/A

[FlorianDeconinck]

LGTM