Add and document pulse analysis helper methods

Context

Add helper methods and documentation to help future developers complete the Pulse Analysis strategy.

Summary

I added 2 methods, checkPulses() and createFitFunction(). These will be needed to complete pulse analysis, but they were done outside of the fit method in the old system. They are now included in the PulseFittingStrategy1 to simplify the process of implementing the remaining pulse analysis functionality. I added these as protected instead of private simply because that's the only way they show up in the Doxygen documentation, which may be helpful for future developers.

These are just sample implementations of these methods and may be different depending on how the pulse analysis is implemented, but the structure will remain the same.

I also added getPulses() to Channel because it was needed in checkPulses(). I know @bheywood has added this as well. We weren't sure if it should return a pointer or not. I currently have it returning a pointer, but if Brodie figures out that it's best to do it another way, it would be a simple change in 4 places in the checkPulses() method.

NumPulsesFit was added to the config file. It was being set manually in the WaveformProcessor and it used in multiple places in pulse analysis.

How was this tested?

I ran the compiled code and it runs as it did before (no Events skipped). I also tried setting the config value Polarity to 1 in the checkPulses method and it skipped all the Events, as expected.