Room list contextual menu (#427)

- Adds `ModalBottomSheet` to our design components (it wraps the homonimous Material3 one).
- Adds  a bottom sheet to the Room list using the aforementioned design component.
- Adds navigation from the room list to a room detail (context menu "Settings" action).
- Consolidates the "leave room flow" into a new `leaveroom` module used by both the room list and the room details.
  - Adds progress indicator to the leave room flow
- Uses new `leaveroom` module in `roomdetails` module too. 

Parent issue:
- https://github.com/vector-im/element-x-android/issues/261

appnav/src/main/kotlin/io/element/android/appnav/LoggedInFlowNode.kt

@@ -135,7 +135,10 @@ class LoggedInFlowNode @AssistedInject constructor(
         object RoomList : NavTarget
 
         @Parcelize
-        data class Room(val roomId: RoomId) : NavTarget
+        data class Room(
+            val roomId: RoomId,
+            val initialElement: RoomFlowNode.NavTarget = RoomFlowNode.NavTarget.Messages
+        ) : NavTarget
 
         @Parcelize
         object Settings : NavTarget
@@ -176,6 +179,10 @@ class LoggedInFlowNode @AssistedInject constructor(
                     override fun onInvitesClicked() {
                         backstack.push(NavTarget.InviteList)
                     }
+
+                    override fun onRoomSettingsClicked(roomId: RoomId) {
+                        backstack.push(NavTarget.Room(roomId, initialElement = RoomFlowNode.NavTarget.RoomDetails))
+                    }
                 }
                 roomListEntryPoint
                     .nodeBuilder(this, buildContext)
@@ -193,7 +200,7 @@ class LoggedInFlowNode @AssistedInject constructor(
                     }
                 } else {
                     val nodeLifecycleCallbacks = plugins<NodeLifecycleCallback>()
-                    val inputs = RoomFlowNode.Inputs(room)
+                    val inputs = RoomFlowNode.Inputs(room, initialElement = navTarget.initialElement)
                     createNode<RoomFlowNode>(buildContext, plugins = listOf(inputs) + nodeLifecycleCallbacks)
                 }
             }

appnav/src/main/kotlin/io/element/android/appnav/RoomFlowNode.kt

@@ -59,7 +59,7 @@ class RoomFlowNode @AssistedInject constructor(
     roomMembershipObserver: RoomMembershipObserver,
 ) : BackstackNode<RoomFlowNode.NavTarget>(
     backstack = BackStack(
-        initialElement = NavTarget.Messages,
+        initialElement = plugins.filterIsInstance(Inputs::class.java).first().initialElement,
         savedStateMap = buildContext.savedStateMap,
     ),
     buildContext = buildContext,
@@ -73,6 +73,7 @@ class RoomFlowNode @AssistedInject constructor(
 
     data class Inputs(
         val room: MatrixRoom,
+        val initialElement: NavTarget = NavTarget.Messages,
     ) : NodeInputs
 
     private val inputs: Inputs = inputs()
@@ -98,6 +99,7 @@ class RoomFlowNode @AssistedInject constructor(
                 navigateUp()
             }
             .launchIn(lifecycleScope)
+        inputs<Inputs>()
     }
 
     private fun fetchRoomMembers() = lifecycleScope.launch {