Support icon SVG accessibility

[PanderMusubi]

Please, first read the section Accessibility under https://icons.getbootstrap.com/#usage

The question is how to extend the icon render marcro to support aria-hidden="true" and aria-label="..."

Suggestion is to add aria-hidden="true" when an icon is rendered without title and without description. When a description is given (which is likely more detailed than a title) use the description in aria-label="...". Otherwise, when a title is given, use that in aria-label="...".