Split dump manager from SmtEngine (#4824)

Split dump manager from SmtEngine (#4824)

Towards splitting SmtEngine.

This moves utilities related to managing information for dumping to its own utility, DumpManager.

Its current responsibilities are to track information about how to print a model, and the implementation of some dumping traces, although its responsibilities should be extended further so that SmtEngine is not responsible for any command dumping. This is future work.