Add flavor reservation configuration

[Mark-Powers]

This adds configuration needed for the blazar flavor plugin.

[Mark-Powers]

@msherman64 Is there a way I can assert a condition on the defaults? I want to ensure
enable_host_reservation nand enable_flavor_reservation

[msherman64]

@msherman64 Is there a way I can assert a condition on the defaults? I want to ensure enable_host_reservation nand enable_flavor_reservation

there's not really a way to do this within the defaults file / config file. You either need to do this in an ansible task (like in prechecks or config steps, in kolla-ansible), or via an external tool like ansible-lint. In chi-in-a-box itself, you're almost limited to the logic that jinja can do.

will blazar fail if both host_reservation and flavor_reservation are enabled?

[Mark-Powers]

Main issue is that our host_reservation code assumes a lot about hosts, and the monitoring fails for some reason. I'm still digging into this.

[codyhammock]

I think that it be more clear and consistent to name these labels with "blazar_", e.g. "blazar_enable_host_reservation".

[msherman64]

Seconding the request to prefix the new variables with blazar_, due to the global namespace.

Additionally, we seem to maintain a list of plugins and their state in kolla-ansible's blazar role:
https://github.com/ChameleonCloud/kolla-ansible/blob/568df787eeba52116c081ba575c60152242d7135/ansible/roles/blazar/defaults/main.yml#L42-L57

And that lets us template the list of plugins in the config file more cleanly:
https://github.com/ChameleonCloud/kolla-ansible/blob/568df787eeba52116c081ba575c60152242d7135/ansible/roles/blazar/defaults/main.yml#L62
https://github.com/ChameleonCloud/kolla-ansible/blob/568df787eeba52116c081ba575c60152242d7135/ansible/roles/blazar/templates/blazar.conf.j2#L20