* Miscellaneous updates TBC
* Disentangled pivot2 module from snap
why:
Wrote as template on top of sync so it can be shared by fast and snap
sync.
* Renamed and relocated pivot sources
* Integrated `best_pivot` module into full and snap sync
why:
Full sync used an older version of `best_pivot`
* isolating download module from full sync
why;
might be shared with snap sync at a later stage
eca5882238