Allow uploading additional stickers

resources/qml/dialogs/ImagePackEditorDialog.qml

@@ -4,6 +4,7 @@
 
 import ".."
 import "../components"
+import Qt.labs.platform 1.1
 import QtQuick 2.12
 import QtQuick.Controls 2.12
 import QtQuick.Layouts 1.12
@@ -78,6 +79,23 @@ ApplicationWindow {
 
                 }
 
+                footer: Button {
+                    palette: Nheko.colors
+                    onClicked: addFilesDialog.open()
+                    width: ListView.view.width
+                    text: qsTr("Add images")
+
+                    FileDialog {
+                        id: addFilesDialog
+
+                        folder: StandardPaths.writableLocation(StandardPaths.PicturesLocation)
+                        fileMode: FileDialog.OpenFiles
+                        nameFilters: [qsTr("Stickers (*.png *.webp)")]
+                        onAccepted: imagePack.addStickers(files)
+                    }
+
+                }
+
                 delegate: AvatarListTile {
                     id: packItem