As a tempest user:
I want to be able to reuse timing data stored in the tempest/.stestr folder across multiple Tempest runs.

So that:
I can safe time when executing Tempest tests.

Definition of Done: 

• It is possible to specify location (e.g., git repository) in the Tempest CR that is storing the timing data (content of .stestr folder)

• When the location of the timing data is provided via the Tempest CR, the test-operator downloads the data prior the the Tempest execution.

• When test-operator finishes the execution of Tempest tests, it pushes changes in the timing data to the location specified in the Tempest CR.

Notes:
At the end of the tests execution Tempest generates data into the .stestr folder. The data contains information about how long it took to Tempest to execute each test (among other things).

Later when Tempest is executed for the second time and the .stestr folder is present it then uses the info from that folder to schedule the tests between the workers more efficiently so that it takes less time to run the tests.

The idea behind this ticket is to make sure that .stestr folder is present at the beginning of each Tempest run and thus safe the time. Note that right now when you execute Tempest in our jobs it always runs without the .stestr folder because we run Tempest each time in a fresh new environment.