Draft: Implement @nuxt/content v3

1. Change Summary

[Describe what is changing, why, and the impact]

• Closes: #342

2. QA Checklist

[This merge request should follow all best practices utilizing our team code standards and our project's development documentation]

• Code Cleanup: Any messages, linter warnings, and/or deprecation warnings are cleaned up in the console
• Tech Debt: I have created, or documented, any fast follow-up work that needs to be done after this MR is merged
• Efficient Code Review: I have tested and reviewed my own changes thoroughly before assigning a reviewer
• Accessibility: Axe tools run and issues addressed
• Cross-browser compatibility: Works on Safari, Chrome, and Firefox
• Analytics and SEO: Compatible with Google Analytics and SEO tools
• Localization checked for regressions

[Provide concise steps to test the changes]

Review App

Production	Review app
https://about.gitlab.com/	https://content-v3.about.gitlab-review.app/platform/

3. Deployment Steps

[List key deployment steps or configurations]

components/common/NextSteps.vue

@@ -33,18 +33,20 @@ const props = defineProps<NextStepsProps>();
 const { locale } = useI18n();
 
 const { data } = await useAsyncData('next-steps', () =>
-  queryContent(`/shared/${locale.value.toLocaleLowerCase()}/next-steps`).findOne(),
+  queryCollection('shared').where('stem', '=', `shared/${locale.value}/next-steps`).first(),
 );
 
+const nextStepData = data?.value?.body;
+
 if (!data) {
   throw new Error(`Error with NextSteps component content`);
 }
 
 const content = computed(() => ({
-  header: props.header || data.value.header,
-  blurb: props.blurb || data.value.blurb,
-  button: props.button || data.value.button,
-  secondaryButton: props.secondaryButton || data.value.secondaryButton,
+  header: props.header || nextStepData.header,
+  blurb: props.blurb || nextStepData.blurb,
+  button: props.button || nextStepData.button,
+  secondaryButton: props.secondaryButton || nextStepData.secondaryButton,
 }));
 
 const buttonHref = computed(() => updateFreeTrialGlmContent(content.value.button?.config.href || ''));