Find a way to detect users location before generating chapters map and centre it on that location

[Tomasz-Kluczkowski]

It would be better to have the chapters map centred on the website user's location. We do not want to use geolocation as this requires asking user's permission and we do not need their exact position (and it is dodgy to ask when website loads). Locating by their IP address is good enough (a fallback should be provided) as we just want to focus map on their country. Find a way to implement this into chapters map generation.