These changes follow guidance from Sandi and from the general DOM specification that the `tabindex` attribute (along with Angular's `isFocusable` and `isTabbable` attributes) should only be included on elements that can be interacted with via mouse clicks or keyboard input.

A number of elements in the degree planner view were non-interactive by design but still were in tabbable. This commit removes tabbing from those non-interactive elements.

Isaac Evavold authored 5 years ago and Isaac Evavold committed 5 years ago

Previously, the alert component only worked with the degree planner view. Now the alert component can be used in any view that supplies a list of alerts.

- Creates DARS view as a child view of the degree planner
- Moves constants resolver services into the degree planner router instead of the app router
- Updates the navigation links so that the degree planner link and the dars link will be appropriately marked as "active"