Add Calamari test tasks, test script

This adds a multi-test task module for Calamari.  There are several major differences with this module than 'standard' test tasks:

1) self-contained (five tasks in this one file)
2) requires external configuration which will not be checked in to public repos (pkg repo credentials)
3) relies on scripts in the teuthology/task/calamari_test directory for 'test' task (tests the REST API)

As such, we can talk about structure.  I originally had this as five task files and a separate util-function module, but I think this is cleaner/less invasive.

I also made it pep8-clean.