Added action type and updated message for reset password, also reducer for logout

[jbpayne]

constants/action-types.js:

Added missing RESET_PASSWORD_SUCCESS and RESET_PASSWORD_FAIL

screens/login/forgot-password.js:

1. Updated the message from "Check your email" to "Please check your email for the password reset link.
   Once you've set a new password, please return to the login screen."

2. Changed styling to match the initial forgot password screen

screens/dashboard/reducers.js:

Added the same LOGOUT_SUCCESSFUL reducer to the dashboard as is in the login screen. This fixes a bug that did not clear the previous session on logout. I also tried to remove the LOGOUT_SUCCESSFUL reducer from login, but then the logout would not return to the login screen; it cleared the session, but remained on the dashboard. So it appears that this reducer is needed on both login and dashboard.

screens/dashboard/index.js:

1. Imported YellowBox from react-native to use ignoreWarnings on this warning:

Setting a timer for a long period of time, i.e. multiple minutes, is a performance and correctness issue on Android as it keeps the timer module awake, and timers can only be called when the app is in the foreground. See facebook/react-native#12981 for more info.
(Saw setTimeout with duration 3299877ms)

2. Imported ScrollView from react-native instead of react-native-gesture-handler to prevent this warning:

Warning: bind(): You are binding a component method to the component. React does this for you automatically in a high-performance way, so you can safely remove this call. See ScrollView

firebase/firebase-js-sdk#97

package-lock.json:

Updated file from a fresh npm install