Tutor-contrib-branding

- feat: Add BRANDING_MFE_PLATFORM_REPO to set a custom frontend-platform
- doc: Update README

- fix: Fix MFE overrides, empty root issue

- fix: Fixed a bug that happened when the plugin was ran from a different directory than the config.yml.

- ref: Refactor download images
- feat: Add BRANDING_HIDE_LOOKING_FOR_CHALLENGE_WIDGET setting

- feat: Allow hiding the Programs tab and the sideber in the learner dashboard
- feat: Make the course image fit in the course card at the learner dashboard.

- feat: refactor BRANDING_THEME_REPOS to allow repo versioning