[file system][ios] Add download and upload in background (#7380)

* [file-system] make downloadAsync work in backgroud

* [file-system] Upload method

* [file-system] Add body to response

* [file-system] Refactor

* [file system] Handle resumable downloads

* [file system] Add background/foreground option

* [file system] Make background session default

* [file system] Apply requested changes

* [file system] Fix typo

* [file system] Apply requested changes

* [file system] Add changelog

* [expo-file-system] Apply requested changes

* [expo-file-system] Fix session lifetime

* [expo-file-system] Refactor

* [expo-file-system] Fix headers

* [expo-file-system] Apply requested changes

* [expo-file-system] Fix lifetime of EXFileSystem

* [expo-file-system] Extract resumables manger

* [expo-file-system] Pass body safely

* [expo-file-system] Pod install

* [expo-file-system] Apply requested changes

* [expo-file-system] Apply requested changes

* [expo-file-system] Apply requested changes

* [expo-file-system] Pod install in bare-expo

* [expo-file-system] EXResumableManager -> EXResumablesManager

* [expo-file-system] Fix error codes