Large State values cache as part of the protocol

[pugachAG]

The idea is to reduce witness size by making validators have frequently used large state values (in practice those values are contract code) cached locally and then excluding them from the state witness storage proof. For more details see “Caching large state values” along with “Top N values as part of the Protocol” sections in the #10780 description.

Somewhat related to near/NEPs#556.

Expected work:

• Evaluate potential witness size reduction to make sure it is still worth the effort
• Chunk header changes to include values to cache
• Mechanism for retrieving values from the nodes tracking the shard (similar to state sync, but for single state values)
• Implementation + testing
• NEP

Part of #11911.