Import pruning

[nomego]

The should be a way to configure the maximum amount of routes that will be maintained when it comes to imports and DOM-elements.
Once that number is hit, least used routes should be pruned along with their imports.

Note: Multiple views might come from the same vulcanized import.

[megheaiulian]

I think this issue no longer makes sense and can be closed. @nomego

[nomego]

Actually this is still relevant but the wording should be changed.
Unless the behavior changed in your refactor?

This issue addresses the opportunity to not wipe routes (but persist them) so the state is unchanged if you navigate back to it, but to do that we must include some kind of (estimated) memory management to know when we should dump views to free memory.