This commit moves all the SPM package metadata update logic, including
pkgmove and slotmove to entropy.spm plugins.
This makes possible to handle the event more reliably. In particular,
Entropy now controls what Portage does, basing on the repository treeupdates
information.
The scenario in where the Portage tree was not updated and the called
"emaint --fix moveinst" did not do what it was supposed to do is now
handled correctly.
f02283523d