[RFE] local indexing directory should have a unique name

[afcollins]

Is your feature request related to a problem? Please describe.
Local indexing is a valuable feature to keep measurements offline. However, the current implementation writes to the same directory (collected-metrics), and subsequent runs overwrite the previous collections.

Describe the solution you'd like
I would like to have a unique collected-metrics directory created for each run.
It seems fitting to use the UUID of the run as part of the folder name, since it is already a unique identifier and would allow trivial mapping between runs and locally indexed metrics.

Describe alternatives you've considered
Scripting outside of kube-burner. i.e. If I run kube-burner with local indexing in a for loop, I add a separate command to move the folder to a unique name after each kube-burner run.