Export existing configuration from App Store Connect as part of Init

**Is your feature request related to a problem? Please describe.**
The existing onboarding flow is good for new users who want to start fresh. New users for existing apps may feel overwhelmed having to do data entry to copy all their metadata into the configuration file.

**Describe the solution you'd like**
An export feature should be added to `cider init` to take the content verbatim in their existing App Store Connect configuration, select the apps they want to store records for, and write them to a new configuration file.

**Describe alternatives you've considered**
None yet.

**Additional context**
None yet.