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Well the systemjs config is obviously what's loading up the Angular scripts.
Other than that, I'm not going to be much help. I have familiarity with AngularJS (the framework previous to Angular -- Google's naming leaves lots to be desired) but not Angular.
Answering whether you need ajax.googleapis.com ..../angular.min.js, the way of referencing Angular library is changed from AngularJS version to later versions of Angular.
Use Angular CLI or any seed which will scaffold the project(skeleton project) for you and it will be inherently included and you will see package.json specifiying the version of angular and other relevant libraries versions.
short answer, use any seed project(skeleton project) of Angular