Add the observability-client and aodh-client plugins to the openstackclient container in next-gen. This will allow us to use the "openstack alarm" and "openstack metric" commands. While it's not required for the user to interact with these commands for our features to work, these plugins could be useful for troubleshooting. Once we have these plugins included, we can modify openstack-must-gather to use them to for example list alarms and list metric names.