Revert the recent dependency and metadata scanning rework

This reverts the following commits:
fbe522d1
278ad007
863888e4
96daf635
cfd83555

This seems to trigger some mconf bugs when built with all feeds
packages, so I will try to find a less intrusive solution before the
release.

Signed-off-by: Felix Fietkau <nbd@nbd.name>