openhpc role bump & dependency pinning

[sjpb]

• Bump openhpc role from v0.9 to v0.12:
  • Empty partitions now display as "n/a"
  • Slurmdbd startup improvements and support for any partition configuration options
  • Support for autoscale (not supported in appliance yet), but does significantly improve slurm.conf templating for faster slurmctld startup and improved role variable documentation.
• Adds link to role READMEs to common environment's group_var files.
• Support adding slurm config parameters to appliance-defined ones via openhpc_config_extra , instead of overriding using openhpc_config.
• Pins all ansible-galaxy requirements
• Remove group vars for old openhpc_tests replaced by hpctests (except for hpl-all test, but that should be added in hpctests role if required).
• Adds a CI status badge to the readme.
• Adds the environment path to smslabs instances, to make it easier to work out what created them
• Changes smslabs environment name (now its also used for CI, not just an example), to prepare for Support autoscaling and test in CI #151