New onboarding (#241)

* delete old onboarding files and code

* add custom FollowButton component to Post, FeedItem, & ProfileCard

* move building suggested feed into helper lib

* show suggested posts/feed if follower list is empty

* Update tsconfig.json

* add pagination to getting new onboarding

* remove unnecessary console log

* fix naming, add better null check for combinedCursor

* In locally-combined feeds, correctly produce an undefined cursor when out of data

* Minor refactors of the suggested posts lib functions

* Show 'follow button' style of post meta in certain conditions only

* Only show follow btn in posts on the main feed and the discovery feed

* Add a welcome notice to the home feed

* Tune the timing of when the welcome banner shows or hides

* Make the follow button an observer (closes #244)

* Update postmeta to keep the follow btn after press until next render

* A couple of fixes that ensure consistent welcome screen

* Fix lint

* Rework the welcome banner

* Fix cache invalidation of follows model on user switch

* Show welcome banner while loading

* Update the home onboarding feed to get top posts from hardcode recommends

* Drop unused helper function

* Update happy path tests

---------

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

src/view/com/profile/FollowButton.tsx

@@ -0,0 +1,57 @@
+import React from 'react'
+import {StyleSheet, TouchableOpacity, View} from 'react-native'
+import {observer} from 'mobx-react-lite'
+import {Text} from '../util/text/Text'
+import {useStores} from 'state/index'
+import * as apilib from 'lib/api/index'
+import * as Toast from '../util/Toast'
+import {usePalette} from 'lib/hooks/usePalette'
+
+const FollowButton = observer(
+  ({did, declarationCid}: {did: string; declarationCid: string}) => {
+    const store = useStores()
+    const pal = usePalette('default')
+    const isFollowing = store.me.follows.isFollowing(did)
+
+    const onToggleFollow = async () => {
+      if (store.me.follows.isFollowing(did)) {
+        try {
+          await apilib.unfollow(store, store.me.follows.getFollowUri(did))
+          store.me.follows.removeFollow(did)
+        } catch (e: any) {
+          store.log.error('Failed fo delete follow', e)
+          Toast.show('An issue occurred, please try again.')
+        }
+      } else {
+        try {
+          const res = await apilib.follow(store, did, declarationCid)
+          store.me.follows.addFollow(did, res.uri)
+        } catch (e: any) {
+          store.log.error('Failed fo create follow', e)
+          Toast.show('An issue occurred, please try again.')
+        }
+      }
+    }
+
+    return (
+      <TouchableOpacity onPress={onToggleFollow}>
+        <View style={[styles.btn, pal.btn]}>
+          <Text type="button" style={[pal.text]}>
+            {isFollowing ? 'Unfollow' : 'Follow'}
+          </Text>
+        </View>
+      </TouchableOpacity>
+    )
+  },
+)
+
+export default FollowButton
+
+const styles = StyleSheet.create({
+  btn: {
+    paddingVertical: 7,
+    borderRadius: 50,
+    marginLeft: 6,
+    paddingHorizontal: 14,
+  },
+})