feat: implement newsletter subscription feature with new forms and database structure

- Added new newsletter subscription functionality to the participation page.
- Created a new `NewsletterForm` component to handle user subscriptions.
- Introduced `NewsletterSubscriptions` collection to manage subscriptions in the database.
- Developed migration script to set up necessary database tables and fields for the newsletter feature.
- Refactored participation content to remove deprecated newsletter phase data and integrate new structure.
- Updated the `Participation` page to utilize the new newsletter form and handle different application phases.

src/app/(frontend)/[[...slug]]/page.tsx

@@ -8,6 +8,7 @@ import NextApp from '@/spa/NextApp'
 import { normalizeApplicationPhaseData, type SpaApplicationPhaseData } from '@/spa/applicationPhase'
 import { normalizeFooterData, normalizeHeaderData } from '@/spa/cmsNavigation'
 import type { CmsRouteCollection, CmsRouteDoc } from '@/spa/cmsRoute'
+import { normalizeNewsletterFormData, type SpaNewsletterFormData } from '@/spa/newsletterForm'
 import { normalizeSiteSettings, type SpaSiteSettingsData } from '@/spa/siteSettings'
 
 export const dynamic = 'force-dynamic'
@@ -104,6 +105,7 @@ export default async function Page({ params }: Args) {
     footer,
     siteSettings,
     applicationPhase,
+    newsletterForm,
     route,
     supportPages,
     preistraeger,
@@ -116,6 +118,7 @@ export default async function Page({ params }: Args) {
     payload.findGlobal({ slug: 'footer', depth: 1 }).catch(() => undefined),
     payload.findGlobal({ slug: 'site-settings', depth: 1 }).catch(() => undefined),
     payload.findGlobal({ slug: 'application-phase', depth: 0 }).catch(() => undefined),
+    payload.findGlobal({ slug: 'newsletter-form', depth: 0 }).catch(() => undefined),
     findRouteDoc(payload, pathname, draft),
     findSupportPages(payload, draft).catch(() => []),
     findList(payload, 'preistraeger', draft).catch(() => []),
@@ -134,6 +137,7 @@ export default async function Page({ params }: Args) {
       footer={normalizeFooterData(footer)}
       siteSettings={normalizeSiteSettings(siteSettings as Partial<SpaSiteSettingsData> | undefined)}
       applicationPhase={normalizeApplicationPhaseData(applicationPhase as Partial<SpaApplicationPhaseData> | undefined)}
+      newsletterForm={normalizeNewsletterFormData(newsletterForm as Partial<SpaNewsletterFormData> | undefined)}
       cmsRoute={{
         collection: route.collection,
         doc: route.doc as unknown as CmsRouteDoc,