Mining multiple shards support

[syntrust]

changes including:

• Allowing miners to create storage files for shards that do not exist in the contract.
• The flag --shard_index can be used repeatedly to create multiple shards using init.sh.

env ES_NODE_STORAGE_MINER=0x123...ab ./init.sh --shard_index 1 --shard_index 2

Note that

1. The shard files will be created in ./es-data ($data_dir) under the name of shard-$(shard_index).dat.
2. The shard will be skipped if the file already exists.
3. The shard 0 will be tried to create if no --shard_index is used.

• The run.sh file will start with data files in ./es-data/shard-*.dat, as well as files specified by --storage.files.
• TestMining in integration_tests/node_mine_test.go has been updated to
  • support L2 contract and
  • call putBlobs to upload blobs
  • be able to reuse a smart contract deployed (previously only newly deployed contract can be used).

Integration test:

env ES_NODE_SIGNER_PRIVATE_KEY=<pk> ./integration_tests/run_tests.sh

Tests:

• An es-node has been initialized and running with an updated contract (Abstract block info storage-contracts-v1#105) deployed on L2 testnet, showing that init and mining multiple shards are working correctly with blobs uploaded.
• An es-node of public testnet on Sepolia has been upgraded to this branch and mining successfully with current storage contracts (before Opening a new shard fix storage-contracts-v1#104 and Abstract block info storage-contracts-v1#105)

Docs update: ethstorage/ethstorage-doc#33