Allow for multiple separate links via custom_html

[consideRatio]

This is a feature to help me able to link to multiple funding organizations etc as relevant in 2i2c-org/infrastructure#2897. If approved, I'll use it to produce something that looks like this:

via configuration like this:

        'funded_by': {
            'name': '',
            'url': '',
            'custom_html': '<a href="https://www.dfg.de/">DFG</a>, <a href="https://www.cessda.eu/">CESSDA</a>, <a href="https://www.gesis.org/">GESIS</a>, FKZ/Project number <a href="https://gepris.dfg.de/gepris/projekt/460234259?language=en">460234259</a>',
        },

[GeorgianaElena]

LGTM