619 restructure local storage (#628)

* To MMKV migration working

* POC migrated font size settings

* Moved settings to mmkv

* Fix typos

* Migrated contexts slice

* Migrated app slice

* POC instance emoji update

* Migrated drafts

* Migrated simple instance properties

* All migrated!

* Re-structure files

* Tolerant of undefined settings

* Can properly logging in and out including empty state

src/utils/startup/timezone.ts

@@ -0,0 +1,12 @@
+import * as Localization from 'expo-localization'
+import log from './log'
+
+const timezone = () => {
+  log('log', 'Timezone', Localization.getCalendars()[0].timeZone || 'unknown')
+  if ('__setDefaultTimeZone' in Intl.DateTimeFormat) {
+    // @ts-ignore
+    Intl.DateTimeFormat.__setDefaultTimeZone(Localization.getCalendars()[0].timeZone)
+  }
+}
+
+export default timezone