* purge_old_snapshot_archives is changed to take an extra argument 'maximum_snapshots_to_retain' to control the max number of latest snapshot archives to retain. Note the oldest snapshot is always retained as before and is not subjected to this new options.
* The validator and ledger-tool executables are modified with a CLI argument --maximum-snapshots-to-retain. And the options are propagated down the call chains. Their corresponding shell scripts were changed accordingly.
* SnapshotConfig is modified to have an extra field for the maximum_snapshots_to_retain
* Unit tests are developed to cover purge_old_snapshot_archives
* Require that blockstore block-time only be recognized slot, instead of root
* Move cache_block_time to after Bank freeze
* Single use statement
* Pass transaction_status_sender by reference
* Remove unnecessary slot-existence check before caching block time altogether
* Move block-time existence check into Blockstore::cache_block_time, Blockstore no longer needed in blockstore_processor helper
* Add ledger-tool for restoring roots to the Roots CF
* Print successful repair data, and repair in chunks
* Add parameter to limit num slots checked for root repair
* Plumb allow-dead-slots to ledger-tool verify
* ledger-tool cleanup and add some useful missing args
Print root slots and how many unrooted past last root.
* Update tonic & prost, and regenerate proto
* Reignore doc code
* Revert pull #14367, but pin tokio to v0.2 for jsonrpc
* Bump backoff and goauth -> and therefore tokio
* Bump tokio in faucet, net-utils
* Bump remaining tokio, plus tarpc
* Configure bigtable's timeout when read-only
* Review comments
* Apply nits (thanks!)
Co-authored-by: Michael Vines <mvines@gmail.com>
* Timeout in the streamed decoding as well
Co-authored-by: Michael Vines <mvines@gmail.com>
