split stepper component into two dialogs, add form validation logic

src/app/app.routing.module.ts

src/app/dars/dars-view/dars-view.component.html

src/app/dars/dars-view/dars-view.component.ts

src/app/dars/dars.module.ts

...p/dars/new-audit-options/new-audit-options.component.html

...p/dars/new-audit-options/new-audit-options.component.scss

...ars/new-audit-options/new-audit-options.component.spec.ts

...app/dars/new-audit-options/new-audit-options.component.ts

...egree-audit-dialog/new-degree-audit-dialog.component.html

...egree-audit-dialog/new-degree-audit-dialog.component.scss

...-degree-audit-dialog/new-degree-audit-dialog.component.ts

...t-if-audit-dialog/new-what-if-audit-dialog.component.html

...t-if-audit-dialog/new-what-if-audit-dialog.component.scss

...hat-if-audit-dialog/new-what-if-audit-dialog.component.ts

src/app/dars/services/api.service.ts