Add queryUsage method to billing services

A new method, queryUsage, has been added to the billing strategy classes and the gateway service to offer usage querying capabilities for Stripe and Lemon Squeezy. QueryBillingUsageSchema has also been introduced in the schema-related changes. Changes also include updates to the functions' comment descriptions. A minor tweak was made to the Button and Link components in the `faq/page.tsx' file.

apps/web/app/(marketing)/faq/page.tsx

@@ -86,8 +86,8 @@ async function FAQPage() {
           </div>
 
           <div>
-            <Button variant={'outline'}>
-              <Link asChild href={'/contact'}>
+            <Button asChild variant={'outline'}>
+              <Link href={'/contact'}>
                 <span>
                   <Trans i18nKey={'marketing:contactFaq'} />
                 </span>