[APP-705] Metrics revamp pt2 (#896)

* export track function from analytics.tsx

* fix create account tracking

* fix tracking sign in

* add custom feed events

* fix type errors

* refactor create post event

* add profile follow & unfollow events

* refactor PostsFeedSliceModel into its own file

* refactor PostThreadItemModel into its own file

* reorganize code a lil bit

* refactor post-thread-item to use post-feed-item model under the hood

* add post events

* add post reply tracking

* track custom feed load more

* track list subscribe and unsubscribe

src/lib/analytics/analytics.tsx

@@ -16,6 +16,8 @@ const segmentClient = createClient({
   trackAppLifecycleEvents: false,
 })
 
+export const track = segmentClient?.track?.bind?.(segmentClient) as TrackEvent
+
 export function useAnalytics() {
   const store = useStores()
   const methods: ClientMethods = useAnalyticsOrig()