Merge pull request 'add: .env.example' (#2) from dev into main

Reviewed-on: #2

.env.example

@@ -0,0 +1,10 @@
+# Added by Payload
+DATABASE_URI=file:./diplomarbeitsportal.db
+PAYLOAD_SECRET=YOUR_PAYLOAD_SECRET_HERE
+NEXT_PUBLIC_SERVER_URL=http://localhost:3000
+CRON_SECRET=YOUR_CRON_SECRET_HERE
+PREVIEW_SECRET=YOUR_SECRET_HERE
+
+AUTH_GITHUB_ID=YOUR_GITHUB_ID
+AUTH_GITHUB_SECRET=YOUR_GITHUB_SECRET
+AUTH_SECRET="YOUR_AUTH_SECRET" # Added by `npx auth`. Read more: https://cli.authjs.dev