Update workshop automation for Sensu Go 6.5.0

[calebhailey]

Changes:

• Use the new sensu-backend init --cluster-admin-apikey automation
• Rename the configurator service to workshop (which can also now be used as a sandboxed workstation environment)
• Remove the sensuctl container (no need for sensuctl configure thanks to automated API Key initialization)
• Remove the wait-for-sensuctl script and .config/ volume mount
• Refactor the seed-workshop-resources script (use a simpler sensuctl retry loop mechanism)

[thoward]

You've done some of this work, but I'm not sure how much is left to do. Can you update the checklist here, and for anything isn't yet complete, create a task-specific issue and link it from the checklist?

[calebhailey]

@thoward I updated the checklist here for the items #106 implements; the only one #106 is missing is also the least useful, so I crossed it off.