We need to implement the whole rpc interface for the state service with replaced local_cache in favour of chain_index

The associated branch #690 adds the necessary chain_index backed fields (namely indexer) and marks all of the local_cached based fields as deprecated.

For any of the following endpoints (sub-issues), the flow should be:

• update the endpoint state_service implementation to not rely on deprecated (non chain_index backed) fields anymore, the compiler will help you with warnings about it
• if you find any significant blockers or problems, please open sub-issues on the dedicated issue for the endpoint you are working on.
• once it's done, PR that work against this branch StateService migration to chainindex backend #677