Extract shell state into separate context (#1824)

* WIP

* Add shell state

* Integrate new shell state for drawer and minimal shell mode

* Replace isDrawerSwipeDisabled

* Split shell state into separate contexts to avoid needless re-renders

* Fix typo

---------

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

src/lib/routes/back-handler.ts

@@ -1,19 +0,0 @@
-import {isAndroid} from 'platform/detection'
-import {BackHandler} from 'react-native'
-import {RootStoreModel} from 'state/index'
-
-export function init(store: RootStoreModel) {
-  // only register back handler on android, otherwise it throws an error
-  if (isAndroid) {
-    const backHandler = BackHandler.addEventListener(
-      'hardwareBackPress',
-      () => {
-        return store.shell.closeAnyActiveElement()
-      },
-    )
-    return () => {
-      backHandler.remove()
-    }
-  }
-  return () => {}
-}