Include HeiGIT and/or oqapi logo on our figures

[matthiasschaub]

Alternatively use text reference:
E.g.

• © 2022 HeiGIT gGmbH
• powered by HeiGIT gGmbH
• powered by ohsome developed at HeiGIT gGmbH

Another alternative would be to not include the HeiGIT logo on figures but disable plotly print/download and add a custom print/download button which creates a PDF with the figure and the description and the HeiGIT logo.

[matthiasschaub]

climate-action/climatoology#244