Improve vehicle init and some bugfixes

[DurgNomis-drol]

Should fix #111 and fix missing await in the last PR #110

This is not a complete refactor of the vehicle init, but a start

[joro75]

Ok. These changes will certainly help.
There are however still two questions, I would like to discuss. See my other comments.

[joro75]

@DurgNomis-drol Question 1:
Why wass the problem with the missing async in the return statement not detected by the unittests?
I'm not into the details of the pylint or mypy, but I now understand that these checkers are not able to check if async/await is used correctly in all cases?
Can we extend the unittests to include an actual test of the code in controller.py to catch this (and other errors) in an earlier stage?

[joro75]

@DurgNomis-drol Question 2:
Now more members of Vehicle are being checked if they are assigned/existing before they are being interrogated. This doesn't sound very pythonic. Wouldn't it be possible to use a customized Dict-type that just returns a default empty Dict if itself, or a member of it is not present? I do realize that this will be an extension on top of the basic python Dict type.
I'm still thinking on how we can find a good solution for the problem that depending on the vehicle for which the data is requested, some (data-)members can be present or not.

I do have an idea, but I will have to try and investigate it a little bit more in detail.

[DurgNomis-drol]

Thanks for reviewing!!

Question 1: The previous PR was created in a different dev environment then i normally use and it is indeed strange that i was not caught back then. This PR was made on my normal setup and there it caught as an error by pylint, so there is something wrong with the first setup I used and the one that is running on github CI, but i am no sure why.

And yes we should extend unitests to cover controller.py as well.

This link may explain why it didn't catch the error: https://stackoverflow.com/questions/64894694/which-python-static-checker-can-catch-forgotten-await-problems though both functions are typed
All the more reason to get this library typed. 😄

Question 2: I am not sure i understand what you mean by using a typed dict for class members? Vehicle init should probably be be rewritten so that we reuse the object when updating instead of creating a new one every time there is new data. Like this:
Init vehicle and then every time we want to update a specific member of the object, we call like this: vehicle.update_hvac() and then this only updates the hvac part. Does this make sense to do?