DJC: Refine the "Check for new Package versions" implementation on Inventory tab

From https://github.com/nexB/dejacode/issues/3#issuecomment-1866902832

> Now, about the "Check for new Package versions", I don't think the current implementation works that well in the context of the pagination. I'm not sure how useful it is to only get the updated information for the current page. I would prefer to rework this implementation as another ticket, returning the whole list of available updates, maybe in a new tab.
Let me know your thoughts.