[FC-0078] App Level Dates Page

[marcotuts]

Goal:
Adds new top level navigation page to see dates across all enrolled courses. For learners in 1 course this will be similar to the experience of accessing the course dates tab.

Figma:
https://www.figma.com/design/iZ56YMjbRMShCCDxqrqRrR/Open-edX-Mobile-App-v2.2?node-id=14160-129105&t=hnrdlJRDMrnQeukj-1

[edschema]

Linking this PR on shifting relative due dates both here and the relevant sub-issue. openedx/openedx-platform#36499. This PR introduces a new API endpoint to allow processing shifting of the dates from the app level page for multiple courses.