Cache expensive endpoints more
Cache expensive endpoints more

Just putting this up there as a potential easy thing that might
alleviate our performance issues in our biggest clusters.

Currently can take ~4s to get state.json so a 5s cache can't be helping
a lot. We could make this configurable if anyone feels strongly?
Otherwise I can't see it hurting that much.

somic/paasta,Yelp/paasta,Yelp/paasta,somic/paasta