Change apollo-angular imports to named non-namespace imports

[gsingh-ut]

Creating a copy of the issue created by @DaSchTour #223 on the older repo.

Is your feature request related to a problem? Please describe.
Because of this thymikee/jest-preset-angular#963 bug, it is not possible to write tests with generated services.

Describe the solution you'd like
Imports for angular-apollo should be changed from import * as Apollo from 'apollo-angular'; to import {Apollo, ...} from 'apollo-angular'

Describe alternatives you've considered

Hacky solutions described in the jest-preset-angular issue like including the generated ts files in tsconfig.spec.json which might have other unknown effects like including too many files which are not required