for-15.05 opkg/packages: Show package size in list of available packages

for-15.05 opkg/packages: Show package size in list of available packages

CC15.05 opkg was patched by https://dev.openwrt.org/changeset/47196
to support the --size option. This commit backports the Luci features:

Add package *.ipk size information to package listing in Luci,
as opkg was today extended to support listing also the size information.
Visible fields are now: name, version, size, description

That will help users considering installation of a certain package
to assess its size impact on flash.

Note: Opkg data includes the size of the .ipk file, not the expanded size.

Signed-off-by: Hannu Nyman <hannu.nyman@iki.fi>
(cherry picked from commit 3288fe76ab3d2269abcf902d0df6f847c6200e8e)