Add cyclic writer

[akaszynski]

Current cyclic writer does support writing out expanded cyclic results. This PR adds that feature and also merges the individual sectors by default. User can override this behavior by setting expand_cyclic=False.

Example:

Plot the Z component of the displacement for the first mode at the 2nd nodal diameter.

# using academic rotor from test_data
filename = 'result.vtk'
academic_rotor.save_as_vtk(filename)

import pyvista as pv
grid = pv.read(filename)
grid.plot(scalars="Nodal solution (0, -2)", component=2)

[RobPasMue]

LGTM!

[akaszynski]

@RobPasMue could we do a patch release for this?

[RobPasMue]

Sure, on it!