Add "trigger on time" functionality
Add the possibility to generate another "software" trigger signal, at a specific moment in time.
Currently, the FMC-ADC device driver initializes the counters in the Time-tag core with the UNIX POSIX time from the host computer (eg. FEC).
It should be possible for the driver to program the gateware to generate a soft trigger when the counters in the time-tag reach a certain value.
This is also a step towards being able to trigger in a distributed way several FMC-ADC cards synchronized over White Rabbit.