Move SnapshotConfig into its own module (#18331)

Also move ArchiveFormat to snapshot_utils, and do not
reexport SnapshotVersion.

core/src/test_validator.rs

@@ -6,10 +6,10 @@ use {
     solana_net_utils::PortRange,
     solana_rpc::rpc::JsonRpcConfig,
     solana_runtime::{
-        bank_forks::{ArchiveFormat, SnapshotConfig, SnapshotVersion},
         genesis_utils::create_genesis_config_with_leader_ex,
         hardened_unpack::MAX_GENESIS_ARCHIVE_UNPACKED_SIZE,
-        snapshot_utils::DEFAULT_MAX_SNAPSHOTS_TO_RETAIN,
+        snapshot_config::SnapshotConfig,
+        snapshot_utils::{ArchiveFormat, SnapshotVersion, DEFAULT_MAX_SNAPSHOTS_TO_RETAIN},
     },
     solana_sdk::{
         account::{Account, AccountSharedData},