showBottomSheet screen action

[Alex009]

Just like dialogs we need showing of bottomsheets, like:

ios:

android:

for android it is BottomSheets but for iOS should be own implementation.

common api is:

expect fun Screen<*>.showBottomSheet(
    content: Widget<WidgetSize<SizeSpec.MatchParent, SizeSpec.WrapContent>>,
   onDismiss: () -> Unit
)

in actual implementation we should create own bottomSheet and insert into body view created from content widget.

[Alex009]

merged. API:

fun Screen<*>.showBottomSheet(
    content: Widget<WidgetSize.Const<SizeSpec.AsParent, SizeSpec.WrapContent>>,
    onDismiss: () -> Unit
)

added as separated module: moko-widgets-bottomsheet and require cocoapod moko-widgets-bottomsheet