Several sections of the code *required* a LocalPackagePool, but they
could still perform their operations with a standard PackagePool.
Signed-off-by: Ryan Gonzalez <ryan.gonzalez@collabora.com>
this change imports downloaded packages into the pool immediately after download.
in case mirroring is aborted and later resumed, already downloaded packages will not be downloaded anymore.
When trying to delete a mirror that has snapshot and not providing the
force option, the API should not return a `500
StatusInternalServerError`.
A `403 StatusForbidden` is more appropriate when the condition is
expected by the server.