feat: add nextcloud notification provider (#5343)

* feat: add Nextcloud notification provider
fix: resolve hydration error in add-board modal

* Update packages/integrations/src/nextcloud/nextcloud.integration.ts

Co-authored-by: Manuel <30572287+manuel-rw@users.noreply.github.com>

* Update nextcloud.integration.ts

* defined notificationSchema outside of class

---------

Co-authored-by: Lorinc936 <lorinc1231@gmail.com>
Co-authored-by: Lorinc936 <116025544+Lorinc936@users.noreply.github.com>

packages/definitions/src/integration.ts

@@ -217,7 +217,7 @@ export const integrationDefs = {
     name: "Nextcloud",
     secretKinds: [["username", "password"]],
     iconUrl: "https://cdn.jsdelivr.net/gh/homarr-labs/dashboard-icons@master/svg/nextcloud.svg",
-    category: ["calendar"],
+    category: ["calendar", "notifications"],
     documentationUrl: createDocumentationLink("/docs/integrations/nextcloud"),
   },
   unifiController: {