* checkpoint database at end of each slot
To avoid spending time on synchronizing with the file system while doing
processing, the manual checkpointing mode turns off fsync during
processing and instead checkpoints the database when the slot has ended.
From an sqlite perspecitve, in WAL mode this guaranees database
consistency but may lead to data loss which is fine - anything missing
from the beacon chain database can be recovered on the next startup.
* log sync status and delay in slot start message
* bump
0f8a3a5ae8