Add exporting individual attributes

Based off #32

Also:
* rework README.md
* improve configuration error messages

.forgejo/workflows/verify.yaml

@@ -5,8 +5,8 @@ on:
       - main
 
 jobs:
-  test:
-    name: Test
+  ansible-lint:
+    name: Verify
     runs-on: docker
     steps:
       - uses: actions/checkout@v7
@@ -14,6 +14,6 @@ jobs:
         run: |
           apt update
           apt install -y maven
-      - name: Run maven verify test
+      - name: Run maven verify
         run: |
-          mvn -f attribute-endpoints-provider --batch-mode --no-transfer-progress verify test
+          mvn -f attribute-endpoints-provider --batch-mode --no-transfer-progress verify

attribute-endpoints-provider/src/main/java/de/ccc/hamburg/keycloak/attribute_endpoints/AttributeEndpointsResourceProviderFactory.java

@@ -1,36 +1,35 @@
 package de.ccc.hamburg.keycloak.attribute_endpoints;
 
+import com.google.auto.service.AutoService;
 import org.keycloak.Config;
 import org.keycloak.models.KeycloakSession;
 import org.keycloak.models.KeycloakSessionFactory;
 import org.keycloak.services.resource.RealmResourceProvider;
 import org.keycloak.services.resource.RealmResourceProviderFactory;
 
-import com.google.auto.service.AutoService;
-
 @AutoService(RealmResourceProviderFactory.class)
 public class AttributeEndpointsResourceProviderFactory implements RealmResourceProviderFactory {
     static final String PROVIDER_ID = "attribute-endpoints-provider";
 
     @Override
-	public RealmResourceProvider create(KeycloakSession keycloakSession) {
-		return new AttributeEndpointsResourceProvider(keycloakSession);
-	}
+    public RealmResourceProvider create(KeycloakSession keycloakSession) {
+        return new AttributeEndpointsResourceProvider(keycloakSession);
+    }
 
-	@Override
-	public void init(Config.Scope config) {
-	}
+    @Override
+    public void init(Config.Scope config) {
+    }
 
-	@Override
-	public void postInit(KeycloakSessionFactory keycloakSessionFactory) {
-	}
+    @Override
+    public void postInit(KeycloakSessionFactory keycloakSessionFactory) {
+    }
 
-	@Override
-	public void close() {
-	}
+    @Override
+    public void close() {
+    }
 
-	@Override
-	public String getId() {
-		return PROVIDER_ID;
-	}
+    @Override
+    public String getId() {
+        return PROVIDER_ID;
+    }
 }

attribute-endpoints-provider/src/test/java/de/ccc/hamburg/keycloak/attribute_endpoints/AttributeEndpointsResourceProviderTest.java

@@ -24,9 +24,7 @@ import java.util.Map;
 import java.util.function.Supplier;
 import java.util.stream.Stream;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertThrows;
-import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.*;
 import static org.mockito.ArgumentMatchers.*;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.when;