rapids_cpm_package_details now validates required entries exist

[robertmaynard]

Description

rapids-cmake now provides proper error message reports when the required json entry fields don't exist in either the root versions.json or the package override.

Checklist

• [x] I am familiar with the Contributing Guidelines.
• [x] New or existing tests cover these changes.
• [x] The documentation is up to date with these changes.
• [x] The cmake-format.json is up to date with these changes.

[robertmaynard]

/merge