feat: remove obsolete dott locations in germany

[LarsBehl]

Context

The removed locations started to response with 'region not found' in the last 7 days. Since the initial 'region not found' response, they did not provide any information again.

What's Changed

This PR removes the 13 locations which started to responde with 'region not found'.

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[richfab]

Hi @LarsBehl,

Thank you for your contribution to systems.csv.

I can see that scooters are currently available in Bielefeld, DE via the Dott app, so the service is still up there.

We remove feeds from systems.csv only when the system has been permanently shutdown.

I will close this PR for now. Hoping Dott will fix the feeds shortly.

Feel free to reopen this PR if you notice cities where Dott has been permanently shutdown.

Best regards,
Fabien (MobilityData)

[LarsBehl]

Hi @richfab,
it might be the case that dott is still operational in these cities, however they do not provide a public gbfs feed. Looking at the global entry point, the removed locations are no longer listed.
It is possible that some issue on dotts side is the main factor. It is also possible, that dott is slowly shutting down the public gbfs feed, as the documentation states, that authentication is needed

Edit:
If feeds that require authentication should also remain in the systems.csv, this change is obsolete

[richfab]

Thanks @LarsBehl for sharing more information.

I've asked Dott for more information about the feed authentication.

If Dott confirms that these feeds require auth, we may keep them in systems.csv with information on how to obtain credentials.

Thank you,
Fabien