feat: Peak finding

[RobBuchananCompPhys]

Part of #1979

This class allows us to do the following peak-related operations on 1D data:

• Find peaks, with the option of specifying a vertical threshold or horizontal isolation to constrain the peaks
• Find their prominences
• Rank them by value from highest to lowest
• Struct containers for peaks provides a way of describing each data peak in terms of their location and peak value
• With the use of isolation, the peak finding can be robust to random noise

[rprospero]

Your numerical methods background is both more recent and more intensive than mine, so my suggestions might be out of line due to my missing crucial details. In that case, many of my comments could be corrected with just some explanatory comments.

[RobBuchananCompPhys]

@rprospero FYI - I attach documentation from Mathworks detailing the prominence algorithm we're using here.