Feedback Work toward making Package Manager to use nonblocking operations

I don't know what obstacles there are now to properly multithread this (I suspect the issues are more on managed processing side) but currently the biggest pain on PM is that every update/removal you do is a blocking operation. You change one thing and you wait for a long time for Unity to process it.

PM tab should just be responsive frontend instead where you could queue operations and get updates on what happened there. If there's no feasible way to do this, then at least allow users to just queue the operations and hit apply once they've changed everything they wanted.

I love PM but the further Unity has gone with packages, more I find just modifying the manifest.json manually on text editor as it's simply many times faster if I need to modify multiple packages at once. This is the exact opposite of what should happen when you have GUI tool like Package Manager.