Today, we have one build queue. Elements are taken from this (the "Build Queue"
list) and put into the "Build Executor Status" list.
This is all fine.

I propose that we split the current build queue into two:
1) A list of the builds that are in the quiet period.
2) A list of the builds that are not in the quiet period.

Items are moved from 1) to 2) when the quiet quiet period expires.
(And moved from 2) to the "Build Executor Status" list when the "Build Executor
Status" list has an open spot, as today).

I think this will give a really nice graphical interpretation of builds
currently in the quiet period.