[jest] schematic does not work with Angular CLI 8 generated projects

[GregOnNet]

# Error
tsconfig.spec.json not found

• tsconfig is now located in the root of the project.
• the location of tsconfig should be read from angular.json

[FrankStrieter]

• store jest.config in root

[Markus-Ende]

We can use @schematics/angular/utility to access Angular workspace:

import { getWorkspace } from '@schematics/angular/utility/config';
import { ProjectType } from '@schematics/angular/utility/workspace-models';