Add sync by bittorrent snapshots (#1160)

* save state

* torrent experiments

* torrent experiment passed

* fixes after merge

* snapshot headers processing passed

* save state

* save state

* download headers works after snapshot processing

* save state

* save state

* save state

* save state

* add lazy load tx to snapshots, increase number of trackers

* save state

* speedup getting info

* change logging

* move to turbo package

* save state

* save state

* save state

* cleanup

* save state

* add test test

* save state

* lmdb debugging

* fix readonly mode

* save state

* fix build

* sync works

* save state

* save state

* save state

* allow cmd stages stageSenders use snapshots

* debugging failed hashing

* remove experimental tests

* remove torrent experimental tests

* fix lint

* extract snapshot wrapper

* metainfo checker

* add remote seeder

* add logs

* update gomod

* remove useless code

* fix lint&remove useless code

* extract verify snapshot to separated command

* skip debug test

* fix test

* change type of seedSnapshot flag

* add eth logger to torrent lib

* skip debug test

* add Close method

* review fixes

* fix lint

Co-authored-by: alex.sharov <AskAlexSharov@gmail.com>
Co-authored-by: Alexey Akhunov <akhounov@gmail.com>