Consider renaming HostOptions::options to something like HostOptions::host_default_overrides to make the relationship more clear.

Likewise for Process defaults, if we have them at this point.

Update 2022-12-13: Renamed issue to refocus on removing GeneralOptions::host_defaults and CliOptions:host_defaults, in favor of using yaml merge keys and dynamic yaml generation tools to push such "templating" outside of shadow itself.