Eliminate fontawesome.com dependency

In the jupyter notebook integration, we inject a request to fontawesome.com:

https://github.com/Open-EO/openeo-python-client/blob/83194d759f94fa21f5e26f692f8a37f49db9af80/openeo/internal/jupyter.py#L132

I am not a lawyer, but as far as I understand e.g. https://law.stackexchange.com/questions/98873/gdpr-compliance-font-awesome, this might be a source of privacy/GDPR issues for entities that provide hosted openEO environments.

Same problem probably with https://github.com/Open-EO/openeo-python-client/blob/83194d759f94fa21f5e26f692f8a37f49db9af80/openeo/internal/jupyter.py#L6

Regardless of the GDPR/privacy issue, it's also not ideal that we have such hardcoded URLs in the package, without any means to override/disable them (e.g. because they stop working for some reason, or, worse, get compromised, like with the polyfill.io domain attack last year)

How can we improve the situation?

• find GDPR-friendly alternatives?
• reduce/eliminate the need for external hosting of these resources?
  • E.g. can the fonts be replaced with embedded SVG?
  • Or are there ways to allow the user to easily "self-host" on their jupyter environment?
• make the URLs configurable is some way to eliminate the hardcoding problem

Start by reading openeo/internal/jupyter.py at lines 6 and 132 to inventory the fontawesome.com requests and how the notebook integration uses them. Compare the proposed alternatives—local or embedded resources, self-hosting, and configurable URLs—and define completion as removing the hardcoded dependency while preserving the integration and documenting the chosen approach.