build: Move more build stuff inside tasks/
build: Move more build stuff inside tasks/

This helps prevent conflicts when we add both i686 and x86_64 builds
for example.

chergert/gnome-continuous,vrutkovs/vrutkovs.github.io,GNOME/gnome-ostree,chergert/gnome-continuous,chergert/gnome-continuous,djdeath/gnome-ostree,vrutkovs/vrutkovs.github.io,djdeath/gnome-ostree,GNOME/gnome-ostree,GNOME/gnome-ostree,djdeath/gnome-ostree,vrutkovs/vrutkovs.github.io