Upload file to s3: make public a file on upload and allow to configure destination folder

New configurations:
- s3folder: (string) folder to save the files inside bucket
- s3publicFiles: (boolean) indicate if should send ACL parameters

Signed-off-by: Lautaro Alvarez <lautarolalvarez@gmail.com>

lib/config/default.js

@@ -76,6 +76,9 @@ module.exports = {
     secretAccessKey: undefined,
     region: undefined
   },
+  s3bucket: undefined,
+  s3folder: 'uploads',
+  s3publicFiles: false,
   minio: {
     accessKey: undefined,
     secretKey: undefined,
@@ -83,7 +86,6 @@ module.exports = {
     secure: true,
     port: 9000
   },
-  s3bucket: undefined,
   azure: {
     connectionString: undefined,
     container: undefined