Feature: Channel by channel gain configuration for opdet deconvolution

[vpec0]

Introducing feature to allow configuration of gains for each channel in the deconvolution algorithm. The gains are used to normalise the output waveform - the SPE templates' amplitudes are normalised to the specified gain (number of ADCs per SPE).

The gains are expected to come within an ascii file: each row specifies the channel number and the gain, separated by whitespace.

The new configurable for the deconvolution module is ChannelGainFile. If it is an empty string, no rescaling is done and the SPE amplitude is equal to the amplitude of the corresponding SPE template.

So far, no checks are done if all channels have the gain set and it is implicitly assumed that they are. The case where only subset of channels have their gains set would lead to a segfault.

[lpaulucc]

It looks good. But should it not have a default value (empty?) for ChannelGainFile when the parameter is read or in the Deconvolution.fcl?

[vpec0]

@lpaulucc Yes, I was thinking about that. I am inclined to keep the configurable without default, but specify an empty string in the default config fhicl. I'll do this when I get back to it. I still need to implement some undefined-situation handling.