[Spike] Explore ways to have synchronous access to EOS contracts

[yarkinwho]

There are always needs for EVM contracts to interact with EOS contracts. Currently, we can do it via bridge messages and call actions. Those operations are clearly asynchronously.

We should explore ways for EVM to access (read or if possible write) EOS tables and contracts synchronously.

The following things should be noted in the design:
0 don't forget node
1 Figure out whether it's feasible to provide a general way for EVM to read any EOS table
2 Take the Sync Call proposal into account (AntelopeIO/spring#933), regardless whether it will be available soon.
3 Figure out whether it's feasible and necessary to provide write access
4 Analysis if we should charge such access and how