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)
Files that contain template instructions should include a `.template` extension to prevent them from
being treated as TypeScript/JSON/etc. files. Not doing so can result in parse errors or other failures
when the files are incorrectly processed by other tools.
Code related to decoding buffers into strings and parsing content into JSON can now be removed by using the
support provided directly from the Tree instance for the executing schematic.
