Updates for all angular.io links to the new angular.dev domain. Additionally, adjustment to new resources where the equivalent does not exist on the new site (e.g. Tour of Heroes tutorial)
Currently, the `readme.md` also contains information on how to build and test the CLI which isn't useful to most users. With this change we move this information into a seperate document.
I wrote down my understanding of the best ways to build/run/test/debug this repository.
A couple other random things included here:
* Removed an extraneous `debugger;` statement which I kept hitting.
* Removed the `watch` scripts which are no longer used and don't need to be supported.
* Removed `yarn test-cli-e2e`, as it alters the $PATH and can use the wrong `ng` instance.
Added types from the commit validation script to CONTRIBUTING. Added
packages names from the package script to the scope section. Added
examples of good commit messages.
Also corrected some texts.
