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)
These async methods are a replacement for the Observable based `runSchematicAsync` and `runExternalSchematicAsync` methods.
DEPRECATED:
The Observable based `SchematicTestRunner.runSchematicAsync` and `SchematicTestRunner.runExternalSchematicAsync` method have been deprecated in favor of the Promise based `SchematicTestRunner.runSchematic` and `SchematicTestRunner.runExternalSchematic`.
This aligns options that do the same thing:
1) `skipSpecs` and `spec` has been deprecated in favor of `skipTests`.
2) `styleext` has been deprecated in favor of `style` since the latest is two words.
Fixes#12784
