Get baseURL from ou_code in bearer token

[RichieB2B]

As discussed in #546. We can get the Fleet URL from the bearer token instead of specifying it in the settings.

This needs testing before merging!

[RichieB2B]

@ngardiner I have tested this code now for using FleetAPI Europe and Owner API tokens. Please test for FleetAPI NA tokens. After that we can merge it.

PS: Owner API tokens still work with this patch because of 4b1767f

[alexeiw123]

I've just pulled this update to test at home and I can no longer access the twcmanager interface.

~/TWCManager $ sudo -u twcmanager python -m TWCManager
Traceback (most recent call last):
  File "/usr/lib/python3.7/runpy.py", line 193, in _run_module_as_main
    "__main__", mod_spec)
  File "/usr/lib/python3.7/runpy.py", line 85, in _run_code
    exec(code, run_globals)
  File "/home/pi/TWCManager/TWCManager.py", line 34, in <module>
    import TWCManager.TWCManager
  File "/home/pi/TWCManager/lib/TWCManager/TWCManager.py", line 636, in <module>
    master.loadSettings()
  File "/home/pi/TWCManager/lib/TWCManager/TWCMaster.py", line 774, in loadSettings
    carapi.setCarApiBearerToken(self.settings.get("carApiBearerToken", ""))
AttributeError: 'NoneType' object has no attribute 'setCarApiBearerToken'

This seems related to this change, if not let me know and I'll create it's own issue.
Edit: Actually I'll go ahead an create an issue