plotting of PTs with non-fixed sample rate

[Nomos11]

Currently, it appears that each PT will be sampled with the given plotting sample rate (since it is turned into a program beforehand) to match what the hardware would put out.

to get a quick overview over the pulse without caring about actual staircase behavior on a hardware, it could be convenient to allow e.g. ConstantPTs or PointPTs wih sparse entries to be sampled at only the actually defined points / at lower rates and have it interpolated implicitly by matplotlib to avoid plotting millions of points for pulse sequences consisting of pulses with completely different timescales.