Make Supermarket Upgrade Process Delightful

[nellshamrell]

Currently Supermarket upgrade process not delightful. These steps would make it more delightful.

1. Modify default recipe so that it attempts all steps necessary to upgrade Supermarket node
2. Document version pinning attribute
3. Compose discrete install/upgrade steps into separate recipes

See #32 for more details

[nathenharvey]

This is also related to TRI-162

[robbkidd]

After some conversations with omnibus maintainers, a proposal for simplifying Supermarket install and upgrade is brewing in my head: deprecate this cookbook in favor of documenting how to write a wrapper cookbook to use chef-ingredient directly. (An example.)

• The chef_ingredient resource has actions for installing a specific version or upgrading Chef's omnibus packages.
• The ingredient_config resource knows how and where to write out the JSON file that an omnibus package ultimately uses for configuration customization.

A human writing their own wrapper would assemble a hash-like data structure of their overrides—from attributes, data bags, vaults, and/or other secrets management—and pass a JSONified version of that structure to ingredient_config. It's simpler and avoids passing secrets around and into this supermarket_omnibus_cookbook as node attributes.