Document known EULA workarounds

[dvx76]

No quite a fix but documenting all known workaround to access the EULA should help new users for now.

Fixes #198, #180

[Farfar]

Nice summary. Can't think of anything else to add.

[Henry2808]

Just my 5 cents as an Enyaq IV owner, might help others:
For me, issues with logging in using the custom integration or other third party apps (such as tibber) only disappeared, when I installed and configured the MySkoda Essentials (!) app and allowed access to profile and car data in that app.
In the documentation, I feel it is important to distinguish the MySkoda app (typically used for Enyaq IV, has a dark green icon on iOS) and the MySkoda Essentials app (not recommended nor needed for Enyaq IV, has a light green icon on iOS). Only in the Essentials app the questions to allow access pop up.