ROENROLL-1583 show disclaimer alert on first app load, hide after dismiss

src/app/core/models/alert.ts

...ee-planner/alert-container/alert-container.component.html

...ee-planner/alert-container/alert-container.component.scss

...gree-planner/alert-container/alert-container.component.ts

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

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

src/app/degree-planner/store/actions/ui.actions.ts

src/app/degree-planner/store/effects/plan.effects.ts

src/app/degree-planner/store/reducer.ts

src/app/degree-planner/store/selectors.ts

src/app/degree-planner/store/state.ts