Wire the sliders into the config file

Not yet the game itself. That's still TODO.

internal/ui/driver.go

@@ -180,6 +180,12 @@ func (d *Driver) ValueInt(id string, into *int) error {
 	return nil
 }
 
+func (d *Driver) SetValueInt(id string, value int) error {
+	vStr := strconv.Itoa(value)
+
+	return d.SetValue(id, vStr)
+}
+
 func (d *Driver) Update(screenX, screenY int) error {
 	// This will be updated while processing hovers
 	d.tooltip = ""