Emptying of "Node-History" Cache

### Feature Idea

When working with higher quantities of nodes or for longer amounts of time, something like a "node-history" appears to get overloaded resulting lags and short freezes of ComfyUI.
A setting allowing to specify the maximum number of cached steps or a maximum amount of memory to be used for it would alleviate this issue.

### Existing Solutions

Saving and reloading the workflow, after closing it once. Or opening a new tab and reloading it there resets the memory consumption too.

### Other

Copy-pasting a few nodes multiple times shows how more and more memory is used, which is alright and expected. Upon deleting them however it adds the entire memory consumption of them on top again. Maybe related to how those nodes are all saved in some history, but ctrl+z does not do anything in my case, so it looks like a waste of memory in the background to me.
Emptying node and model caches does nothing about that issue.