New algorithm for managing resources on shared plans

@levon, @philip, @blueback09 – kicking off a performance discussion here: Performance Q&A guide

Re: @philip – "Would people on the Team plan still need to pay more if you decide to allow a purchasable performance increase? "

Probably not. We’re still working out how it would work, but we’d likely use a performance increase as a replacement for the current limits on workflow runs, so we’d probably reshuffle the whole plan structure to take it into account.