Automatic merge from submit-queue

[WIP/RFC] Rescheduling in Kubernetes design proposal

Proposal by @bgrant0607 and @davidopp (and inspired by years of discussion and experience from folks who worked on Borg and Omega).

This doc is a proposal for a set of inter-related concepts related to "rescheduling" -- that is, "moving" an already-running pod to a new node in order to improve where it is running. (Specific concepts discussed are priority, preemption, disruption budget, quota, `/evict` subresource, and rescheduler.)

Feedback on the proposal is very welcome. For now, please stick to comments about the design, not spelling, punctuation, grammar, broken links, etc., so we can keep the doc uncluttered enough to make it easy for folks to comment on the more important things. 

ref/ #22054 #18724 #19080 #12611 #20699 #17393 #12140 #22212

@HaiyangDING @mqliang @derekwaynecarr @kubernetes/sig-scheduling @kubernetes/huawei @timothysc @mml @dchen1107