Add TFTP service

The next service has been implemented: TFTP. You might think this is the most useless service, but with such small implementations it is much easier to test the framework. For example i found out that the user management is not as powerful as it should be. The problem is that tftpd-hpa runs as user ‘nobody’ per default, but the shared folder UI does not allow to set permissions for that user -> i had rework that soon.

TFTP service
TFTP service