Add Analytics package (#46)

* Add Analytics package

Created a new analytics package with a manager to handle tracking of events and page views. The package includes a default provider that can be switched out and uses a NullAnalyticsService if no provider is registered. Additional types, scripts, and package configuration are also provided to support development.

* Add marketing components for UI package

Introduced new React components under "marketing" for the UI package. These include 'Pill', 'GradientSecondaryText', 'Hero', 'CtaButton', 'FeatureCard', 'FeatureGrid', 'FeatureShowcase', 'GradientText', 'Header', and 'SecondaryHero'. Updated 'package.json' to export these components. Replaced the implementation of 'Home', 'SiteHeader', and 'SiteFooter' with these components for cleaner code and better reusability.

packages/billing/gateway/src/components/pricing-table.tsx

@@ -189,7 +189,7 @@ function PricingItem(
           <div className={'flex items-center space-x-6'}>
             <b
               className={
-                'text-current-foreground font-heading tracking-tight font-semibold uppercase'
+                'text-current-foreground font-heading font-semibold uppercase tracking-tight'
               }
             >
               <Trans
@@ -341,7 +341,7 @@ function Price({ children }: React.PropsWithChildren) {
     >
       <span
         className={
-          'font-heading flex items-center text-3xl font-bold lg:text-4xl tracking-tighter'
+          'font-heading flex items-center text-3xl font-bold tracking-tighter lg:text-4xl'
         }
       >
         {children}