file actions: add bucket and endpoint to notifications

The HTTP notifications are now invoked as POST and the notification is
a JSON inside the POST body.

This is a backward incompatible change but this way the actions can be
extended more easily, sorry for the trouble

Fixes #101

sftpd/ssh_cmd.go

@@ -454,7 +454,7 @@ func (c *sshCommand) sendExitStatus(err error) {
 				realPath = p
 			}
 		}
-		go executeAction(operationSSHCmd, c.connection.User.Username, realPath, "", c.command, 0, vfs.IsLocalOsFs(c.connection.fs))
+		go executeAction(newActionNotification(c.connection.User, operationSSHCmd, realPath, "", c.command, 0))
 	}
 }