fix #4849: ui: allow decompressing ISO files when downloading

fix #4849: ui: allow decompressing ISO files when downloading

The compression algorithm will be automatically detected when querying the
download URL. It can be overriden by the user using the "compression algorithm"
drop down under advanced.

Signed-off-by: Philipp Hufnagl <p.hufnagl@proxmox.com>
Reworded title and message, updated d/control for libpve-storage-perl version
Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
Reviewed-by: Dominik Csapak <d.csapak@proxmox.com>
Tested-by: Dominik Csapak <d.csapak@proxmox.com>