Several large refactors to land this:

- Removed RefreshableUiState
- Reworked UiState to allow data, error, and loading at the same time (to support all use cases)
- Removed effects architecture and restructured using ViewModel
- Refactored Repository to expose Flow and suspend functions throughout
- Deleted JetNewsStatus global state

Composables of screens were refactored to follow hoisting best practices
- Each screen has a single stateful composable paired with a stateless composable at the top level
- Stateful composabels use ViewModel to manage state
- Added slots where appropriate to avoid too many parameters

ArticleScreen:
- Moved favorites to ViewModel from JetNewsStatus
- Refactored composables to use new state

HomeScreen:
- Renames to make composables names match their function
- Added slot to LoadingContnent to extract a composable focused on initial load and swipe to refresh
- Renamed HomeScreenBodyWrapper to HomeScreenErrorAndContent to better match function
- Added empty UI state if the initial load fails ("Tap to load content")
- Hoisted snackbar state to ViewModel and made HomeScreenErrorAndContent stateless
- Renamed all composables related to displaying the post list to PostList from HomeScreenBody etc.
- Used unidirectional data flow throughout post list composables
- Renamed LoadingHomeScreen to FullScreenLoading to better match function
- Animated ErrorSnackbar on entrance and exit using AnimatedVisibility

InterestsScreen:
- Introduced TabContent object to describe a tab and it's composable content, this allows for slot usage for screen-level composables
- Stateless InterestScreen now takes a List<TabContent> which describes the tabs and their content
- Renamed InterestScreenBody to TabContent to better match function
- Moved selected topics to ViewModel, and removed global state
- Renamed *Tab composables to *List composables (e.g. TopicList) to better match function
- Removed string-key from topics, and introduced TopicSelection for TabWithSections
- Moved all previously global state into Repository (which is a singleton)
- Use unidirectional data flow throughout this screen

SwipeToRefreshLayout:
- Added TODO to document a know bug (b/164113834) that this code works around
- Disable swiping when state.value == true to avoid a bug created by duplicated state showing an infinite loading spinner

…effect similar to the previous architecture.

Re-add ViewModel when https://issuetracker.google.com/issues/165642391 is fixed

Changes:
- Created launchUiStateProducer effect to safely call suspending data producers from compose and return refreshable UI state
- Removed ViewModel from HomeScreen, InterestsScreen and ArticleScreen
- Refactored stateful screen composables to use the new loading effect