`convert` from SparsePolynomialZonotope to Taylor model

[schillic]

This branch is based on #3440 and #3446.

One commit added convenience functions from ReachabilityAnalysis to construct important intervals (zero_itv/sym_itv). There are two follow-up tasks related to them.

• There was a ToDo to generalize them to other numeric types, so I did that. But that implies that currently every call creates a new instance. We could have a dictionary instead that stores these instances, or just store the Float64 one because that is the one we would use in practice. But this can be done in a later step.
• We should then use these functions in ReachabilityAnalysis.

[schillic]

@mforets do you also indirectly approve #3440, which this branch is based on?