Add capability to set the number of output points per element in the parameters file

[stvdwtt]

By default, deal.II outputs only the nodal values. However, for higher order elements this makes the solution appear choppier than it is in reality. In PRISMS-PF we compensate for this by adding interior points as the degree goes above one. For quadratic elements we bisect the elements for output. For cubic we break it into three. However, given the increased accuracy per DOF, this undersells the accuracy, so some users might want to output an even higher resolution sampling. Users may also want to lower it to reduce the file size.

Instead of using the degree directly, this should be a parameter controlled by the input file.