ECOM-4216 Styling the header

lms/static/js/learner_dashboard/views/program_header_view.js

.../js/spec/learner_dashboard/program_details_header_spec.js

lms/static/sass/_build-learner-dashboard.scss

lms/static/sass/elements/_banners.scss

lms/static/sass/views/_program-details.scss

lms/templates/learner_dashboard/program_details.html

...mplates/learner_dashboard/program_details_view.underscore

...emplates/learner_dashboard/program_header_view.underscore