devel/cirrus-cli: New Port

Command line interface for Cirrus CI

Cirrus CLI is a tool for running containerized tasks reproducibly in any
environment. Most commonly, Cirrus tasks are used as part of continuous
integration workflows but can also be used as part of local development
process as a hermetic replacement of helper scripts/Makefiles. Cirrus
CLI runs your tasks locally the same way they are executed in CI or on
your colleague's machine. Immutability of containers ensures the tasks
will be executed the same way years from now regardless what versions
of packages you'll have locally.

WWW: https://github.com/cirruslabs/cirrus-cli

Currently this port does not come with a rc script for the worker to
start as I am working on it. But this can be achieved manually.