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
* Option "--disable-ext-msg-broadcast"
* "Get shard out queue size" query
* Move disabling ext msg broadcasts from command-line arguments to config
* Fix compilation error
* Asynchronous store_cell and gc in celldb
* Make GC in celldb work evenly over time
* Increase timeouts for downloading blocks
* Reuse blocks from previous rounds in validator session
* Use Rldp2 in FullNode for downloading persistent states and archives
* Improve logs in download-archive-slice and download-state
* Decrease delay between serializing shards
* Make CellDbIn::load_cell synchronous to avoid interfering with store_cell
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Co-authored-by: SpyCheese <mikle98@yandex.ru>
