Implemented AmazonS3PathPrefix (#14917)

* Implemented AmazonS3PathPrefix

* Remove unecessary method

* fix for test

* fix for test which are failing

* fix for test which are failing

* fix for test

Co-authored-by: Dusan Panic <dusan@salestrekker.com>

app/plugin_test.go

@@ -498,6 +498,7 @@ func TestPluginSync(t *testing.T) {
 				cfg.FileSettings.AmazonS3AccessKeyId = model.NewString(model.MINIO_ACCESS_KEY)
 				cfg.FileSettings.AmazonS3SecretAccessKey = model.NewString(model.MINIO_SECRET_KEY)
 				cfg.FileSettings.AmazonS3Bucket = model.NewString(model.MINIO_BUCKET)
+				cfg.FileSettings.AmazonS3PathPrefix = model.NewString("")
 				cfg.FileSettings.AmazonS3Endpoint = model.NewString(s3Endpoint)
 				cfg.FileSettings.AmazonS3Region = model.NewString("")
 				cfg.FileSettings.AmazonS3SSL = model.NewBool(false)