Migration for tsconfig solution style rollback

[d-koppenhagen]

Is your feature request related to a problem? Please describe.
Within Angular 10, the TypeScript config files had been refactored to use the tsconfig solution style.

This feature will be reverted within one of the next minor versions as it causes some probnlems.
There are already PRs for Angular and the Angular CLI.

Describe the solution you'd like
This change affects the NativeScript schematics for Angular as the referenced file that'll be touched by the schematics must be changed back from tsconfig.base.json to tsconfig.json.

Describe alternatives you've considered

Additional context
See also the Twitter thread of @vsavkin related to this change.