Avoid code duplication for signal processing

Some functions seems duplicated within TRestDetectorSignal and TRestRawSignal, for instance GetSignalSmoothed, GetBaseLine and GetBaseLineSigma.

I propose de following:

• Implement generic methods for signal processing that should be agnostic of the original signal event.
• Speed up data processing by extracting different parameters such as baseline, baselineSigma, threshold integral, risetime, maxPeak and so on using a single loop (funcion).
• The new class or namespace for signal processing should lie inside framework since I believe it should be generic for different libraries (rawlib detectorlib and connectorslib)