Implement inner Enclosure approximations

[lgeretti]

According to "Utilizing Dependencies to Obtain Subsets of Reachable Sets" from Kochdumper-Schurmann-Althoff, we can compute inner approximations from (Taylor) outer approximations with polynomial cost, which makes sense when we are interested in jointly proving/disproving.

This applies to dynamics because it needs the initial set and the actual dynamics, since the solution needs to be validated through backwards reachability.