Does DNN track modules/pages creation/last update dates. If yes, where are these dates stored?

If you are asking if DNN tracks when the module content, such as wth the text/html, is last updated, or when the Settings, such as security settings, of a page or module are changed, I'll agree with Sebastian.

If you are asking if DNN tracks when the module was first/last uploaded or when a new page is created/updated - I'm going to say it does; In the Event Log.
If you look at the 'Types' you can limit the report to, you will find 'Module Created', 'Module Updated', plus some more, same for a tab, 'Tab Created', 'Tab Updated'.

Module Updated is a confusing term in this topic since it can apply to 2 things, content or settings. I'll try to be more concise:

The event log tracks when a module has been uploaded (as created or updated) and tracks when a Tab has been created or has had its settings modified.

The event log does not track when a module has had its settings updated, or the content.

If I have any of that wrong, I'm totally misunderstanding the event log, so I'll need some correcting. :)