Move remaining code to app module

There's still some stuff that could potentially go elsewhere but I think it's enough for now.

src/app/qml/EditMenu.qml

@@ -0,0 +1,86 @@
+// SPDX-FileCopyrightText: 2021 Carson Black <uhhadd@gmail.com>
+// SPDX-License-Identifier: LGPL-2.0-or-later
+
+import Qt.labs.platform as Labs
+import QtQuick
+import QtQuick.Layouts
+
+Labs.Menu {
+    id: root
+
+    required property Item field
+
+    Labs.MenuItem {
+        enabled: root.field !== null && root.field.canUndo
+        text: i18nc("text editing menu action", "Undo")
+        shortcut: StandardKey.Undo
+        onTriggered: {
+            root.field.undo();
+            root.close();
+        }
+    }
+
+    Labs.MenuItem {
+        enabled: root.field !== null && root.field.canRedo
+        text: i18nc("text editing menu action", "Redo")
+        shortcut: StandardKey.Redo
+        onTriggered: {
+            root.field.undo();
+            root.close();
+        }
+    }
+
+    Labs.MenuSeparator {}
+
+    Labs.MenuItem {
+        enabled: root.field !== null && root.field.selectedText
+        text: i18nc("text editing menu action", "Cut")
+        shortcut: StandardKey.Cut
+        onTriggered: {
+            root.field.cut();
+            root.close();
+        }
+    }
+
+    Labs.MenuItem {
+        enabled: root.field !== null && root.field.selectedText
+        text: i18nc("text editing menu action", "Copy")
+        shortcut: StandardKey.Copy
+        onTriggered: {
+            root.field.copy();
+            root.close();
+        }
+    }
+
+    Labs.MenuItem {
+        enabled: root.field !== null && root.field.canPaste
+        text: i18nc("text editing menu action", "Paste")
+        shortcut: StandardKey.Paste
+        onTriggered: {
+            root.field.paste();
+            root.close();
+        }
+    }
+
+    Labs.MenuItem {
+        enabled: root.field !== null && root.field.selectedText !== ""
+        text: i18nc("text editing menu action", "Delete")
+        shortcut: ""
+        onTriggered: {
+            root.field.remove(root.field.selectionStart, root.field.selectionEnd);
+            root.close();
+        }
+    }
+
+    Labs.MenuSeparator {}
+
+    Labs.MenuItem {
+        enabled: root.field !== null
+        text: i18nc("text editing menu action", "Select All")
+        shortcut: StandardKey.SelectAll
+        onTriggered: {
+            root.field.selectAll();
+            root.close();
+        }
+    }
+}