Misc improvements to GenericAdapter

- Allow removing one item from the list
- Keep track of one selected position. This is useful for single choice lists using radio buttons
- Max number of displayed entries. An expand button will be displayed at the bottom when going past the limit, and the entries to display when collapsed is configurable

app/src/main/java/emu/skyline/adapter/GenericAdapter.kt

@@ -36,6 +36,7 @@ class GenericAdapter : RecyclerView.Adapter<GenericViewHolder<ViewBinding>>(), F
     val currentItems : List<GenericListItem<in ViewBinding>> get() = asyncListDiffer.currentList
 
     var currentSearchTerm = ""
+    var selectedPosition : Int? = null
 
     private val viewTypesMapping = mutableMapOf<ViewBindingFactory, Int>()
 
@@ -68,6 +69,11 @@ class GenericAdapter : RecyclerView.Adapter<GenericViewHolder<ViewBinding>>(), F
         filter.filter(currentSearchTerm)
     }
 
+    fun removeItemAt(position : Int) {
+        allItems.removeAt(position)
+        filter.filter(currentSearchTerm)
+    }
+
     fun setOnFilterPublishedListener(listener : OnFilterPublishedListener) {
         onFilterPublishedListener = listener
     }