only some necessary apis are implemented.

apply `Eth.Miner.GasCeil` to TxPool even the node did not enable `--mine` option
Otherwise, there could be accmulated pending transactions in txpool.
Take an example:
- Currently, BSC testnet's block gaslimit is 70M, as 20M gas is reserved for
  SystemTxs, the maximum acceptable GasLimit for transaction is 50M.
- TxPool recevied a transaction with GasLimit 60M, it would be accepted in TxPool but it
  will never be accepted by validators. Such kinds of transactions will be kept in txpool
  and gradually make the txpool overflowed

)

Bumps [actions/download-artifact](https://github.com/actions/download-artifact) from 3 to 4.1.7.

Otherwise the node will be waiting for 500ms before the block fetcher
keeps processing.

This PR tries to improve #2680
If the node did not set `Eth.Miner` in config.toml, the default GasCeil
will be 30000000, it is not an accurate number for both BSC mainnet and testnet.
Set it to 0 means disable the transaction GasLimit check, i.e. the TxPool will
accept transactions with any GasLimit size.

others changes:
  - remove bsc-docker, as it is broken
  - remove light client, as it is no longer supported

…)"

This reverts commit 0c0958f.

eth/handler: remove duplicate check for lists in body