Remove banned users structure and handle reasonCode in validateAuthToken

...html5/imports/api/meetings/server/modifiers/addMeeting.js

.../imports/api/meetings/server/modifiers/meetingHasEnded.js

...l5/imports/api/users/server/handlers/validateAuthToken.js

...tton-html5/imports/api/users/server/methods/removeUser.js

...ml5/imports/api/users/server/methods/validateAuthToken.js

...utton-html5/imports/api/users/server/store/bannedUsers.js

...on-html5/imports/ui/components/error-screen/component.jsx

bigbluebutton-html5/imports/ui/services/auth/index.js

bigbluebutton-html5/public/locales/en.json