Coordinate transformations

[RudolfWeeber]

In context with #3960, coordinate transforms are needed.
In the particular case, Cartesian -> cylindrical with basis vectors and origin not identical.

To my understanding, the most general solution is to split this into

1. translation to align the origins
2. basis transform to align the basis vectors
3. convert Cartesian to cylindrical coordinates for matching basis vectors. I.e. theta=0 would refer to the x axis, theta=pi/2 to the y-axis and z =z.

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1. is probably not worth a function, since it is vector subtraction.

2. The second part can be done most general (supporting also non-orthogonal coordinates)
   using a transformation matrix containing the new basis vectors (as columns, i guess)
   This only requires matrix vector product which is in the utils library.
   https://en.wikipedia.org/wiki/Change_of_basis

3. theta using atan2 (the one that can deal with four quadrants, r=sqrt(x^2+y^2), z=z

The reverse would look like:
x = r cos(theta), y = r sin(theta), z=z

To reverse 2., the caller has to use the original basis transform with the inverse transformation matrix.
Matrix inversion can be taken from boost::qvm

[RudolfWeeber]

This is done, i guess.