[APP-615] COPPA-compliant signup (#570)

* Rework account creation to be COPPA compliant

* Fix lint

* Switch android datepicker to use the spinner mode

* Fix type signatures & usages

package.json

@@ -38,6 +38,7 @@
     "@react-native-camera-roll/camera-roll": "^5.2.2",
     "@react-native-clipboard/clipboard": "^1.10.0",
     "@react-native-community/blur": "^4.3.0",
+    "@react-native-community/datetimepicker": "6.7.3",
     "@react-navigation/bottom-tabs": "^6.5.7",
     "@react-navigation/drawer": "^6.6.2",
     "@react-navigation/native": "^6.1.6",