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)
This change first attempts to resolve a schematic referenced via the external schematic rule from the requesting schematic collection. This allows schematic packages that are direct dependencies of another schematic package to be used with the external schematic rule without manual package resolution code within the schematic.
Closes#18098Closes#11026
