[enh] #140 remove asyncio and aiohttp in tests

tests/api/bma/test_blockchain.py

tests/api/bma/test_bma.py

tests/api/bma/test_network.py

tests/api/bma/test_tx.py

tests/api/bma/test_wot.py

tests/api/bma/test_ws.py

tests/api/webserver.py

tests/api/ws2p/test_ws2p.py

tests/helpers/ws2p.py