Feature/path-activities (#213)
* refactor: inject API key through DirectionsRepository constructor
* test: update tests to accommodate API key in DirectionsRepository
* refactor: modify factory to include API key injection
* test: update tests to adapt for the API key in DirectionsViewModelTest
* feature: add DirectionsViewModel in MainActivity
* build: add MAPS_API_KEY to BuildConfig for DirectionsViewModel
* feat: add path between activities
* test: update tests in ActivitiesMapScreenTest to handle paths between Activities
* test: add new legs and activity
* format: format to ktfmtFormat
* fix: filter out activities with invalid locations
