refactor of notes to observables

package-lock.json

package.json

src/app/core/data.service.spec.ts

src/app/core/data.service.ts

src/app/core/models/course-details.ts

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

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

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

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

...se-details-dialog/course-details-dialog.component.spec.ts

.../course-details-dialog/course-details-dialog.component.ts

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

...anner/dialogs/notes-dialog/notes-dialog.component.spec.ts

...favorites-container/favorites-container.component.spec.ts

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

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

...e-planner/term-container/term-container.component.spec.ts

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

...pp/shared/course-details/course-details.component.spec.ts

src/app/shared/course-details/course-details.component.ts