Evaluate switch from commonjs to system module format for TS

[dsebastien]

Currently, in the tsconfig.json file, we define commonjs as the module format that TypeScript should generate. I've done this in the past to fix some issues (can't remember which ones :p), but maybe we could switch to system: https://github.com/dsebastien/modernWebDevGenerator/blob/master/app/templates/projectFiles/tsconfig.json