project dearchive: show lsat known size of files in banner

[haraldschilly]

while the project is stopped, the database still knows the most recent disk usage. display it with a warning that this information is stale in the quota console row for the disk usage.

the above is already fixed,this is now the comment below

[williamstein]

Also, when you open an archived project it says:

"Project is being copied from longterm storage; this may take several minutes depending on how many files you have."

CoCalc very likely knows "how many files you have", in a sense, weighted by size. We could show that information right there...