HaikuDepot: Refreshing after install/uninstall needs to be much more light-weight

[stippi]

Currently, there is no difference between the user manually refreshing the package list, and adopting the package list after installing/uninstalling a package. The later should be much more light-weight, it will scale very badly. What should probably happen, is that the Package Manager in the system is queried, and only the package status is updated for each package. Right now, it throws away everything and rebuilds the entire list, then re-reads the haiku-depot-web information. Even from the file cache, this is much too slow. One effect is that packages lose all their translations in the list, and then regain them sometime after.

[stippi]

Implemented in hrev48721.