[Theming] As a user, I want to be able to apply accent (secondary) colours

[clukhei]

Prerequisites

• I have searched for duplicate or closed feature requests
• I have read the contributing guidelines

Proposal

Create new semantic accent colour tokens , and accent tone for components .

Follow the current naming convention --sgds-product-primary-100, suggesting
---sgds-product-accent-100

Accent is similar to the term "secondary" used in other design system.

Motivation and context

SGDS Primary , Secondary Tertiary translates in form to default, outline, ghost

However, in terms of colour there is no secondary/tertiary colour.
Currently only product brand colour exists.