Make texts fields selectable by mouse for various components

This enables mouse-selectable for
- The image reader dialog
- Layer view text field (in simulation view)
- The TextField with unit component (for instace used to set the scale
 of models)
- Rename dialog(s)
- Currency text field
- The settings filter text field

CURA-8684

resources/qml/Preferences/GeneralPage.qml

@@ -216,6 +216,7 @@ UM.PreferencesPage
                 TextField
                 {
                     id: currencyField
+                    selectByMouse: true
                     text: UM.Preferences.getValue("cura/currency")
                     onTextChanged: UM.Preferences.setValue("cura/currency", text)
                 }