Constraints-based offer filtering

This epic tracks work for implementing offer constraints for the scheduler API, i.e. an interface for frameworks to specify constraints on agent attributes in offers.

By specifying offer constraints, a "picky" framework can greatly reduce a time needed to get a suitable offer, especially in the case when the corresponding role is close to be out of quota.

One example which receives a huge benefit from offer constraints is running a "daemon set": when a framework needs to launch a task on every node of a large cluster, but the quota is just enough for all these tasks.

Design doc: https://docs.google.com/document/d/1MV048BwjLSoa8sn_5hs4kIH4YJMf6-Gsqbij3YuT1No/edit#heading=h.wq9atl6k4yq0