[APP-775] Add Welcome screen after account creation (#1038)

* add comments to step 1-3

* add onboarding screen

* add analytics for onboarding tracking

* fix useEffect

* change text

* change icon size

* put onboarding into bottom sheet modal instead of react navigation

* wip

* Simplify the type validation

* Fix: only trigger onboarding modal when account creation succeeds

* Add the 'session-ready' event which fires when the new session is stable

* Use the 'session-ready' event to trigger the onboarding modal

* update copy

* update copy

---------

Co-authored-by: Paul Frazee <pfrazee@gmail.com>

src/lib/analytics/types.ts

@@ -117,6 +117,9 @@ interface TrackPropertiesMap {
   'MultiFeed:onRefresh': {}
   // MODERATION events
   'Moderation:ContentfilteringButtonClicked': {}
+  // ONBOARDING events
+  'Onboarding:Begin': {}
+  'Onboarding:Complete': {}
 }
 
 interface ScreenPropertiesMap {

src/lib/async/timeout.ts

@@ -0,0 +1,3 @@
+export function timeout(ms: number): Promise<void> {
+  return new Promise(r => setTimeout(r, ms))
+}