[coreboot] Changes to the coreboot Project Structure -- one small step for bike sheds

[mrnuke]

Let's think of a few things which makes gerrit annoying:

* -2 is a de-facto veto
* -1 is not persistent on updates, encouraging -2 to be given

The end result is that we're encouraging vetoing of patches.

Proposal:
* Submitability of a patch is based on overall review score
** Need at least a score of +2 for patch to be submitted
** Maybe (?) a score of +3 to require at least two sets of eyes
* A review of -2 is not a veto
** Patch still submittable if overall score is +2 (or +3)
* Score of -1/-2 is persistent until reviewer retracts it

Requiring a review of +2 is possible, but not necessarily needed. Since only 
persons with +2 rights can submit a patch, their submitting a patch based on a 
+1/+1 review is effectively an approval.

This has the effect of increasing the significance of -1/+1 scores, which, in 
the old scheme, were somewhat useless (an infinite number of -1 scores would 
not prevent a patch from being submitted).

I think we should try this system, and see how well it works.

Alex