Migrate Tutorial to use Test Starter setup

[maxreichmann]

JIRA: CPOUI5FOUNDATION-967
Dev Guide to Test Starter: https://ui5.sap.com/#/topic/032be2cb2e1d4115af20862673bedcdb

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Changes in every exercise:

• Update app code to use Test Starter
• Update documentation in README.md
• Update ui5.yaml config
• Update deps in package.json

Exercises done:

• ex0
• ex1
• ex2
• ex3
• ex4
• ex5
• ex6

Note:
Tests of ex1 and ex6 are runnable and pass.
Tests of ex2 to ex5 are also runnable. But since these tests didn't pass in the original version of this tutorial, they cannot pass now.

Misc. Changes:

• docs(ex0): Replace command for retrieving the version of the installed generator-easy-ui5 npm package

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Generator Template:

• Migrate generator/generators/app/templates to use Test Starter

[akudev]

nice catch