Add Icon Contribution template to Spec Utilities

[amritadesmet]

Problem: Currently, consumers share their icon requests using inconsistent formats in Figma.

Solution: Create an icon contribution Figma boiler template for consumers to fill in when submitting icon requests. Based on Paul's initial design, template will include suggested icon name, design explorations, synonyms etc. This will streamline our internal process with fewer follow-ups.

Avocet goal: Branch reviewed by @pseys