Epic: Label API

[Luckette]

From what I (bucky) understand after talking with Stacie, here's what we need to do from a very high level perspective

1. create a simple caching system for the labels fetched from the new API (most likely done through local storage)
   • we need to be very judicious about cache busting
2. build system to fetch labels from the api and cache them
   • we'll probably keep this code dark (i.e. not being run by users) but still hitting the API
3. switch over to the new resources-with-labels apis
   • realistically, this will happen piecemeal, rather than all-at-once. E.g. we'll do dashboards first, then after we're confident it works, we'll do another resource, like tasks
   • included in this is to stop calling the old labels api
4. improve UX around the resource that is using the new labels apii. In the case of dashboards, we'd update the search that it also searches labels associated with dashboards