## Implement MinimumJerk class

See https://gepgitlab.laas.fr/loco-3d/curves/issues/1

this trajectory allows to execute a rest-to-rest trajectory (0 initial and final velocity and acceleration) from point A to point B in a given amonut of time `T`

by minimizing the time integral of the squared jerk, i.e:

`\min\int_0^T \left(\frac{{\mathrm d}^3 x}{{\mathrm d}t^3}\right)^2 {\mathrm d}t`

This amounts to a fifth-order polynomial with appropriate coefficients. So, normally, if generic polynomials are already implemented, then a separate class may not be strictly needed, but this is a common use case and it might be nice to have it (not to mention that a dedicated implementation might behave better numerically). Details on the implementation can be found in class MinimumJerk.

Implementation should either inherit from polynomial or simply be a static method that create a polynomial with the right coefficients from the given 2 points and time interval.