[components] Merge https://github.com/mozilla-mobile/android-components/pull/7240

[components] Merge https://github.com/mozilla-mobile/android-components/pull/7240

7240: Issue https://github.com/mozilla-mobile/android-components/issues/468: Define initial set of design axioms. r=csadilek,Amejia481,jonalmeida,NotWoods,psymoon a=pocmo

Hey folks. Issue https://github.com/mozilla-mobile/android-components/issues/468 has been around for a while and I took the time this sprint to try to define an initial set of design axioms for AC.

See those axioms as a set of generic "base rules" that define how we want to build our components and what is important to us. I do not intend to dictate those. See this PR as a proposal and that's why I will flag you all for review. Mostly I tried to capture what we have been following already... but we never wrote it down somewhere. Let me know what you think and then we can tweak as needed.

Also do not see them as "set in stone". We can adapt and complement them along the way. For example I feel like we should have something about "performance", "security" or "privacy" in here too eventually.

Here some other examples of axioms that I looked at:
- http://www.gwtproject.org/makinggwtbetter.html#designaxioms
- https://www.designprinciplesftw.com/collections/design-axioms
- http://www.mit.edu/~juhan/design_axioms.html

Co-authored-by: Sebastian Kaspari <s.kaspari@gmail.com>