improve SourceVITA49 to support sampling rate detection and handling

[James-Wang-JM]

Testing with a device which is a VITA49 transmitter. Configure the device to transmit a VITA49 stream which conveys short IQ data. The sampling rate of IQ data is 25kHz

Launch component SourceVITA49 in sandbox and configure it to receive the VITA49 stream, plot port data from dataShort_out and plot port FFT from dataShort_out, observe the labeling of x axis of both plottings.

In time domain plotting, the x axis shows from [0, 1000s], which is not correct and should divide by 25K to be [0, 0.04s].

In frequency domain plotting, the x axis shows from [-0.5Hz, 0.5Hz], which is not correct and should multiply by 25K to be [-12.5kHz, 12.5kHz].

The following code snippet from function SourceVITA49_i::process_context() in SourceVITA49.cpp shall relate to detect and handle the sampling rate.

    if (!_bulkioPriority) {
        ...
            if (!isNull(contextPacket_g->getSampleRate())) {
            outputSRI.xdelta = 1.0 / contextPacket_g->getSampleRate();
            inputSampleRate = contextPacket_g->getSampleRate();
            LOG_DEBUG(SourceVITA49_i, "Sample Rate: " << contextPacket_g->getSampleRate());
        }
    }

[RedhawkDeployer]

For this issue, please provide the version of REDHAWK and OS, so we can try to replicated.

[James-Wang-JM]

Redhawk 2.2.4 on CentOS 7.7.1908 in VirtualBox 5.2.10