Ad-hoc TFTP server driver

[flxzt]

It would be nice to be able to start a tftp server in an ad-hoc way on a remote machine through a driver when it is needed in addition to the current TFTPProvider <-> TFTPProviderDriver resource/driver pair which requires an existing deployment.

This would make the delopyment of the infastructure easier and allows for more flexibility and robustness when for example booting over TFTP in a strategy. Then it could be ensured that for example the path of the TFTP server always matches the uboot tftp string.