This commit contains some parts of https://github.com/ton-blockchain/ton/tree/accelerator
This is auxiliary code that mostly does not change node behavior.
1) Semiprivate overlays and other improvements in overlays code
2) Rename actual_min_split -> monitor_min_split, fix building shard overlays
3) Loading block candidates by block id from DB, fix accept_block after validator restart
4) Cells: ProofStorageStat and changes in CellUsageTree
5) Remove some unused code, other minor changes
* Cache runSmcMethod queries to LS
* Drop duplicate sendMessage
* Drop sendMessage cache once a minute
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Co-authored-by: SpyCheese <mikle98@yandex.ru>
