how do i create a configuration file for Mail Contacts & Calendars
what: how do i create a configuration file for Mail. why: so that default behavior can be portable - font, color, rules, etc... how:
OS X El Capitan (10.11.6), iCloud
Those settings are stored in the com.apple.mail.plist file inside the com.apple.mail Container (~/Library/Containers).
You would have to write a script it insert those items as the preference list contains account information and other account specific settings.
You may be able to start with a base plist which doesn't have any account information, but I don't know if Mail will replace the entire plist when a user first opens Mail.