Instances can adjust colors in cookie consent

[aboydnw]

Context

GHGC would like to customize colors of the cookie consent bar to better match the overall site theme before turning on. We should make it so each instance can customize this to the colors that best match their theme. Pasting some direction from Sandra below, originally given in slack:

I think we can just create a ticket for that then to make those properties exposable/customizeable on cookie consent component and then worry about uswds tokens later once they are more defined and set since it can be tackled separately. Should just be an easy update of changing the colors to the tokens later

Acceptance Criteria

• Each instance can customize the colors of the cookie consent alert popup

[aboydnw]

@paridhi-parajuli @Jeanne-le-Roux heads up that we are pulling this ticket into this sprint. Our idea is that we will allow the styles on the cookie consent form to be set to the same values as the instance theme, so you could set it to the same color as the nav bar, buttons, etc.

Is it okay if @snmln reaches out to you with any specific questions on how that gets implemented?