[APP-690] better handling of post languages language filtering (#893)

* add SelectLangBtn

* memoized objects that are created to reduce re-creation on re-render

* add langs when uploading post

* only send the top 3 languages otherwise backend will throw error

* mv ContentLanguagesSettings to folder

* add post languages settings modal and state

* fix typos

* modify feed manip to also check langs label on post

* Fix tests

* Remove log

* Update feed-manip.ts

* Fix syntax errors

* UI tuneups

* Show the currently selected languages in the composer

* fix linting

* Use a bcp-47 matching function

* Fix a duplicate language issue

* Fix web

* Dont include lang in prompt

* Make select language btn an observer

* Keep device languages on top of language selection UIs

* Fix android build settings

* Enforce a max of 3 languages in posts

* Fix tests

* Fix types

---------

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

src/platform/detection.ts

@@ -1,4 +1,6 @@
 import {Platform} from 'react-native'
+import {getLocales} from 'expo-localization'
+import {dedupArray} from 'lib/functions'
 
 export const isIOS = Platform.OS === 'ios'
 export const isAndroid = Platform.OS === 'android'
@@ -10,3 +12,7 @@ export const isMobileWeb =
   // @ts-ignore we know window exists -prf
   global.window.matchMedia(isMobileWebMediaQuery)?.matches
 export const isDesktopWeb = isWeb && !isMobileWeb
+
+export const deviceLocales = dedupArray(
+  getLocales?.().map?.(locale => locale.languageCode),
+)