Mention values and values hierarchy when making decisions

Spin-off from !34993 (merged).

Currently the 'making decisions' section of our leadership page doesn't mention values at all, which isn't accurate: we use our values for making decisions all the time. This could probably be more prominent, but I'll start by just adding them (don't wait, MVC, make a proposal, etc.).

@edjdev as you kindly reviewed the other MR, could you take a look here please?