Unify types in hafbe endpoints

1. Exception handling for non existing account in account APIs
2. Exception handling for non existing witness in witness APIs
3. Exception handling block number higher than current head-block
4. Unified result types in all hafbe endpoints that resulted in pattern changes in:

• get_input_type - unified result in "input_value", always return string array
• get_latest_blocks - ops_count object renamed to operations (to unify the returned object with blocksearch)
• renamed total_operations to total_votes in votes history API
• renamed total_operations to total_witnesses in witnesses API

5. Missed blocks parameter moved to sync (unstable API performance when calculated in runtime)