Fix photo & camera permission management (#140)

* Check photo & camera perms and alert the user if not available (close #64)

- Adds perms checks with a prompt to update settings if needed
- Moves initial access of photos in the composer so that the initial prompt
  occurs at an intuitive time.

* Add react-native-permissions test mock

* Fix issue causing multiple access requests

* Use longer var names

* Update podfile.lock

* Lint fix

* Move photo perm request in composer to the gallery btn instead of when the carousel is opened

yarn.lock

@@ -11133,6 +11133,11 @@ react-native-pager-view@^6.0.2:
   resolved "https://registry.yarnpkg.com/react-native-pager-view/-/react-native-pager-view-6.1.2.tgz#3522079b9a9d6634ca5e8d153bc0b4d660254552"
   integrity sha512-qs2KSFc+7N7B+UZ6SG2sTvCkppagm5fVyRclv1KFKc7lDtrhXLzN59tXJw575LDP/dRJoXsNwqUAhZJdws6ABQ==
 
+react-native-permissions@^3.6.1:
+  version "3.6.1"
+  resolved "https://registry.yarnpkg.com/react-native-permissions/-/react-native-permissions-3.6.1.tgz#73adcc1cef8cd57a9ef167b4507405f4ff5749c4"
+  integrity sha512-fzPpPQXeD34inUccqtoResSwYubfrwUguP4qrVUUv8+KSMjYSaHGoS5HaIJLZHlN9gO+TvLJZ2L5ZljTsb6qnQ==
+
 react-native-progress@^5.0.0:
   version "5.0.0"
   resolved "https://registry.yarnpkg.com/react-native-progress/-/react-native-progress-5.0.0.tgz#f5ac6ceaeee27f184c660b00f29419e82a9d0ab0"