Update Basemaps URL and attributions

[skgsergio]

Summary

This PR updates basemaps URL to the new CDN URL and fixes the attributions to match current requirements. It also changes our old name from CartoDB to CARTO (although looks that basemaps names are internal and not exposed to the user, we could skip this if has any kind of side-effects on existing basemaps and just change URL and Attributions).

Full context

We've recently changed our CDN (last week) and we have a plan mid-long term (depends on how quick we manage to stop all the traffic there) to deprecate our .global.ssl.fastly.net domains.

Reviewing the history of this project at some point it used the *.basemaps.cartocdn.com endpoints but were changed because of the lack of HTTPS, which is not an issue anymore.

Additional stuff

Just as a suggestion I'd add to the attributions <a> properties target="_blank" rel="noopener", this way if a user clicks on it doesn't close the Grafana dashboard but opens it in a new tab.

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[amotl]

Dear Sergio,

may we humbly ask you to submit this PR to our grafana-map-panel fork? The vanilla Worldmap Panel has not been maintained for some time already. We would be happy to accept your contribution.

Just as a suggestion I'd add to the attributions <a> properties target="_blank" rel="noopener", this way if a user clicks on it doesn't close the Grafana dashboard but opens it in a new tab.

Sure, go ahead!

With kind regards,
Andreas.

[skgsergio]

Thanks, @amotl will do it.

[amotl]

Thanks for grafana-toolbox#74, Sergio! That was really quick.

[novohool]

Thanks, @amotl will do it.

Thanks for panodata#74, Sergio! That was really quick.