Extend "fpga" binary with "pipe" sub-command

[Steffen Vogel]

Currently, the "fpga" binary only executes benchmarks.

For our first use of VILLASfpga, we would need a "pipe" subcommand which prints all received data in human readable format to stdout and sends all data from stdin to the FPGA.

[Steffen Vogel]

This has been done in a separate streamer command

[Steffen Vogel]

closed via commit 86fab24