organize structure of tests

hived/database_api/find_smt_token_emissions.py

hived/database_api/find_smt_tokens.py

hived/database_api/find_vesting_delegation_expirations.py

hived/database_api/find_vesting_delegations.py

hived/database_api/find_votes.py

hived/database_api/find_withdraw_vesting_routes.py

hived/database_api/find_witnesses.py

hived/database_api/get_active_witnesses.py

hived/database_api/get_config.py

hived/database_api/get_current_price_feed.py

hived/database_api/get_dynamic_global_properties.py

hived/database_api/get_feed_history.py

hived/database_api/get_hardfork_properties.py

hived/database_api/get_nai_pool.py

hived/database_api/get_order_book.py

hived/database_api/get_potential_signatures.py

hived/database_api/get_required_signatures.py

hived/database_api/get_reward_funds.py

hived/database_api/get_transaction_hex.py

hived/database_api/get_version.py