proposal: table contract support iteration

[lispking]

Proposal Details

In many business scenarios, it is necessary to perform iteration operations on the table.

Although this may incur relatively high gas costs, it still has certain applicability for some scenarios with small amounts of data.

Therefore, users can be clearly prompted at the interface to use this method when dealing with small data volumes, which will also make the implementation of the contract more straightforward and easier.

[jolestar]

Finished in #3142