Cookie Consent - Clean up

[snmln]

Notes from feedback on original Cookie Consent Form work:

• Currently, the scripts that check cookies run every time a new page loads which I am not sure if it is necessary.
• (might be related to 1.) I feel like Layout component is doing too much of cookie-related works, which should not be a part of layout's job. It might be slightly complicated in real life since it is layout's job to decide whether to render a specific component or not. But maybe there is something in the middle ground.
• Banner and CookieConsent expects different forms for its content, Banner expects html and CookieConsent expects markdown. I am fine with either of them, but we should consolidate them.

• Consolidate Banner and CookieConsent, wether they both should accept HTML or markdown within config props.
• Extract Cookie consent functionality from the layout component.
• Run Cookie validation scripts only when necessary (this might require further discussion to define upper and lower boundary of when is and is not necessary)