Acceleration of the balance bootstrapping process

Hi! is there a way (e.g. some rosetta-cli config option) to speed up the balance boostrapping process? Unfortunately, to bootstrap 85,000 balances it takes more than 10 hours (on a quite performant server).

**To Reproduce**
1) generate a big `bootsrap_balances.json` file with 85,000 accounts for example
2) start the rosetta-cli data check

**Expected behavior**
I assume that the bootstrap process is faster. IOTA nodes for example need to be boostrapped with the same data and it takes (when optimized) less than a minute.

**Additional context**
IOTA full-nodes are able to start up from a more recent block instead of having to synchronize from genesis. This can be achieved by booting the IOTA full-node with a so called **snapshot**. A snapshot represents the ledger state at a certain block.
Starting from that loaded state, the IOTA node then syncs with it's peers.
To test our implementation we need to boot rosetta-cli with the same snapshot data (therefore we do have such a big `bootstrap_balances.json` file).