Remove logic about form steps

[wbazant]

Unfinished from #415. Nothing uses the steps, but the LocationForm code still tries to be generic.

Part of a bit of a plan:

• easiest to do on top of Use existing translation keys #640 because of the inevitable merge pain
• helps with Make add location more like edit location process #604 and Form edits are lost when coming back from settings #546.

Note for myself for that second part: we need a way to save form values outside of the form, i.e. pass a callback that saves form values on click of the settings button or the "back" button, outside of formik context. But we can't save on every click (or remake the callback) every time the values change, because dispatch() is too slow to happen so much. I think the solution is to access the reference to values, and in Formik this is done through passing a prop called innerRef:

+const FormikAllSteps = ({ children, renderButtons, ...props }) => {
+  const formRef = useRef()
+  console.log('TODO make a callback that saves this value:', formRef.current?.values)
+  return (
+    <Formik
+      innerRef={formRef}