Add icons for common product-conformity standards

[darrellrossman]

These are product markings for three of the most common conformity standards:

• CE - SVG source: https://single-market-economy.ec.europa.eu/single-market/ce-marking_en
• UKCA - SVG source: https://www.gov.uk/guidance/using-the-ukca-marking
• FCC - SVG source: https://www.fcc.gov/logos