Feat：add missing parameter state_class

[DoraTiger]

1. add optional parameter for SPEC_PROP_TRANS_MAP, in order to add default state_class and unit：

{
    'entities':{
        '<entity name>':{
            'format': set<str>,
            'access': set<str>
        }
    },
    'properties': {
        '<property instance name>':{
            'device_class': str,
            'entity': str,
            'optional':{
                'state_class': str,
                'unit_of_measurement': str
            }
        }
    }
}

2. Modify the relevant logic to adapt to parameter modifications.

Relation Issue: #30

[SusanPhevos]

And #245

[topsworld]

if 'state_class' in optional:
result['state_class'] = optional['state_class']

The same logic below

[DoraTiger]

fixed, and test pass in local ha.