Document Configuring Infra with Infra

Is your feature request related to a problem? Please describe.

Every Infra user needs to manage how Infra runs on nodes. We provide a series of resources for doing this, but zero documentation on how to do it. This is one of those key places where customers are falling over because we've never given guidance on a thing they need to actually use the product.

Describe the solution you'd like
Create a document that covers these topics:

• Setting up Infra Client to run on a schedule with one of the platform specific resources
  • chef_client_systemd_timer
  • chef_client_scheduled_task
  • chef_client_cron
  • chef_client_launcd
• Using the chef_client_config resource to push out configuration
• Using chef_client_trusted_certificate resource to push out new certs
• Using the /ohai directory in cookbooks to push out custom ohai plugins

Describe alternatives you've considered
A clear and concise description of any alternative solutions or features you've considered.

Additional context
Add any other context or screenshots about the feature request here.

Start by reviewing the existing Infra documentation structure and the listed Infra Client resources: chef_client_systemd_timer, chef_client_scheduled_task, chef_client_cron, chef_client_launcd, chef_client_config, chef_client_trusted_certificate, and the /ohai cookbook directory. The documentation is done when it explains scheduling, configuration, trusted certificates, and custom Ohai plugins with usable examples.