Boskos is a tool that allows one to create a pool of cloud projects
(definitely GCP, I think it supports other providers as well), and
manages acquiring, releasing, and cleaning them between leases.
We use it for Tekton test infrastructure for our end to end tests and
we'd like to use it for our catalog Tasks as well.
This commit adds boskos acquire and release Tasks.
The acquire Task also creates a pod in the running cluster to perform
heartbeating so that boskos knows that the resource is still in use.
The intention of the release Task is that it would be run in a
Pipeline's `finally` clause, however today that would be difficult
because finally Tasks can't yet use the results of other Tasks, but this
functionality is on the way: https://github.com/tektoncd/pipeline/issues/2557
This is part of the work in #373 to create a Pipeline for the catalog.
