support for delete uploaded files

.meteor/versions

...ges/rocketchat-file-upload/client/lib/FileUploadGridFS.js

packages/rocketchat-file-upload/package.js

...hat-file-upload/server/config/configFileUploadAmazonS3.js

...tchat-file-upload/server/config/configFileUploadGridFS.js

packages/rocketchat-file-upload/server/lib/FileUpload.js

...s/rocketchat-file-upload/server/lib/fileUploadResponse.js

packages/rocketchat-file-upload/server/lib/requests.js

...ges/rocketchat-file-upload/server/lib/responseAmazonS3.js

server/methods/deleteMessage.coffee