Refactor to use observables

src/app/core/config.service.ts

src/app/core/data.service.ts

src/app/core/service/degree-planner-data.service.ts

src/app/degree-planner/degree-planner.component.html

src/app/degree-planner/degree-planner.component.ts

src/app/degree-planner/degree-planner.resolver.ts

src/app/degree-planner/degree-planner.routing.module.ts

...-planner/dialogs/notes-dialog/notes-dialog.component.html

...ee-planner/dialogs/notes-dialog/notes-dialog.component.ts

...er/favorites-container/favorites-container.component.html

...nner/favorites-container/favorites-container.component.ts

...ree-planner/shared/course-item/course-item.component.html

...egree-planner/shared/course-item/course-item.component.ts

...lanner/sidenav-menu-item/sidenav-menu-item.component.html

...-planner/sidenav-menu-item/sidenav-menu-item.component.ts

...gree-planner/term-container/term-container.component.html

...degree-planner/term-container/term-container.component.ts

...d/components/course-details/course-details.component.html

...d/components/course-details/course-details.component.scss

...omponents/course-details/course-details.component.spec.ts