Added new FFT methods UI to simplify TimeSeries instance methods
This PR adds a new module gwpy.signal.fft.ui to simplify calling the relevant gwpy.signal.fft.{lal,scipy} methods using the registry from the TimeSeries object.
This PR adds a new module gwpy.signal.fft.ui to simplify calling the relevant gwpy.signal.fft.{lal,scipy} methods using the registry from the TimeSeries object.