Replace md5 module with hashlib

fix following pylint error:

************* Module connectors.ConnectorBase
connectors/ConnectorBase.py:7: [W1648(bad-python3-import), ] Module moved in Python 3
************* Module runtime.PLCObject
runtime/PLCObject.py:33: [W1648(bad-python3-import), ] Module moved in Python 3

{
    "ID": "wamptest", 
    "active": true, 
    "protocolOptions": {
        "autoPingInterval": 60, 
        "autoPingTimeout": 20
    }, 
    "realm": "Automation", 
    "url": "ws://127.0.0.1:8888"
}