* feat: return response merged from base config, mfe config and mfe overrides
* test: adjust existing tests
* test: add new test methods
* fix: add blank line
* fix: remove homepage_overlay_html
* fix: typo in a comment
* test: change dict merge order to follow the correct hierarchy
* fix: change response keys to uppercase
* fix: add enable_course_discovery
* fix: change COURSES_ARE_BROWSABLE to NON_BROWSABLE_COURSES
* fix: remove show_homepage_promo_video
* fix: use None as default for promo video youtube id
* docs: expand docstrings, rename method/variables
* fix: remove is_cosmetic_price_enabled field