Metrics: Spread index report creation latency buckets

Currently the default latency buckets are not fit for purpose when dealing with index report creation latencies (currently .005, .01, .025, .05, .1, .25, .5, 1, 2.5, 5, 10 seconds).

This needs to be a pair of pull requests, one for Clair and one for app-interface where the SLOs/prometheus rules/prometheus rule tests will need to be updated.