Add sociallogin app to Nextcloud

We would like to login to Nextcloud with our Keycloak instance, to do this we
will use the sociallogin plugin which allows setting up OIDC login with a custom
provider.

Change-Id: I84d430abb3ce75f1dffcfabaed3ea22fa2f51610
diff --git a/modules/nextcloud.nix b/modules/nextcloud.nix
index 9605bfc..9ae147a 100644
--- a/modules/nextcloud.nix
+++ b/modules/nextcloud.nix
@@ -38,6 +38,13 @@
         extraTrustedDomains = [ "nextcloud.clicks.codes" "docs.clicks.codes" ];
     };
 
+    services.nextcloud.extraApps = {
+        sociallogin = pkgs.fetchNextcloudApp {
+            url = "https://github.com/zorn-v/nextcloud-social-login/releases/download/v5.5.3/release.tar.gz";
+            sha256 = "sha256-96/wtK7t23fXVRcntDONjgb5bYtZuaNZzbvQCa5Gsj4=";
+        };
+    };
+
     sops.secrets.nextcloud_admin_password = {
         mode = "0600";
         owner = config.users.users.nextcloud.name;
@@ -45,4 +52,4 @@
         sopsFile = ../secrets/nextcloud.json;
         format = "json";
     };
-}
\ No newline at end of file
+}