sys: use "Auto-Installed" field for packagelist

sys: use "Auto-Installed" field for packagelist

A change to the build scripts (openwrt/openwrt#14428) removed the "user" flag
from all installed packages in the rootfs. This caused problems for tools
like "auc" which rely on the rpcd packagelist command to determine which
packages to request when building a new image.

This change modifies the packagelist implementation to use the "Auto-Installed"
field rather than the "user" flag in order to filter dependencies from the
returned list of packages. The resulting package list is identical without
relying on the semantics of the "user" flag which is typically used to
indicate which packages have been interactively installed by the user.

Signed-off-by: Justin Klaassen <justin@tidylabs.app>
[use 'bool' instead of 'int' type for booleans]
Signed-off-by: Daniel Golle <daniel@makrotopia.org>