Get additional information from Blood Glucose and record as Sensor Attribute

[lunarok]

Checklist

• I have filled out the template to the best of my ability.
• This only contains 1 feature request (if you have multiple feature requests, open one feature request for each feature request).
• This issue is not a duplicate feature request of previous feature requests.

Is your feature request related to a problem? Please describe.

Take Blood Glucose value, it's very important to know if the measurement is before or after meal.
Google Fit has this type of information.

Describe the solution you'd like

Will be nice for some sensors to be able to pull additional informations and record it as "attributes" in HA.
Seems self._attr_extra_state_attributes['meal '] = 2 in sensors.py could be a way. With some method to get second value like blood pressure systolic.

Blood Glucose have few ones, Blood Pressure could be nice also to add Systolic and position as attribute.

Describe alternatives you've considered

Another way could be to add sensors to fetch those values, but attributes allow to keep "context".
If exporting values (to external DB like InfluxDB) or reading by API, attributes allow to see all informations related to each other in a single way.

Additional context

Seems on https://github.com/YorkshireIoT/ha-google-fit/blob/main/custom_components/google_fit/api.py it will be a major impact as parsing of API is mainly done per sensor.

No idea if this will be easly/moderate/complex to achieve. And don't think I could do it alone this one :)