"tenant" label to cinder_volume_gb metric

[az-blip]

Hi, I needed the tenant name label in the cinder_volume_gb to make so regex aggregation, so I suggest a patch to add it. In order to map the tenant id into name, I created a function in keystone.go to generate a map. Il could be reused for the same need in other metrics. I also adapted the tests, they seem to be ok. Tell me if you see something that need to be modified.

Thank you, best regards.

[Sharpz7]

Hey @az-blip . Thanks for this!

We use GPG signing in this repo, you will need to force-commit with verified commits. Let me know if you need help with this.

[az-blip]

Hi, After an intense struggle, I think I finally managed to sign my commits without messing up the repository. Please let me know if it seems ok or if I have to fix something else.

[Sharpz7]

Thanks @az-blip ! Just the tests to do.

I appreciate getting verified commits is a pain, sadly that is out of my control (I am a maintainer not an admin)

[az-blip]

Hi, I fixed the two linter errors. Running the workflow in my forked repository now ends in the "Build and test" step because I didn't configure the registry credentials. I assume (and hope ;) ) it will run smoothly in this repository.

[Sharpz7]

Apoligies for it not auto running @az-blip , it will after your first contribution - which is hopefully soon!

Thanks again :)