Add ability to add an aria-label attribute to icons

This issue about adding the possibility to associate a label to an icon, so that its aria-label attribute can be set: a text explaining what the icon stands for will then be made available to assistive technologies, in case no visible text is already available.

References:

• https://www.w3.org/WAI/WCAG21/Techniques/aria/ARIA24
• https://fontawesome.com/v5.15/how-to-use/on-the-web/other-topics/accessibility