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)
The `root` property is required in a workspace project. Now we issue an actionable warning message when this is missing.
Note: this will become an error in the next major version.
Closes: #21310
The `@schematics/angular` package now contains a defined set of package `exports` including a `utility` subpath export.
A wildcard export is also temporarily defined to support transition away from existing deep-import usage.
The `@schematics/angular/utility` subpath export will contain supported utility methods used by the first-party schematics
contained within the `@schematics/angular` package and can be considered public API that will follow SemVer stability constraints.
The first group of utilities introduced in this change are used to modify the `angular.json` workspace file
within the schematics and include the `updateWorkspace` rule and `readWorkspace`/`writeWorkspace` helpers.
