[SPARK-31352] Add .asf.yaml to control Github settings

### What changes were proposed in this pull request?

Jira: https://issues.apache.org/jira/browse/SPARK-31352
We added this to Apache Airflow project ([PR](apache/airflow#6689)) and I think it would be good to have the Spark's website at the top.

Also, this would allow Spark's PMC Members and committer to control common Github project settings by themselves without having to ask Apache INFRA team.

More info: https://cwiki.apache.org/confluence/display/INFRA/.asf.yaml+features+for+git+repositories

We (Airflow PMC and Committers) used this file to enable Github issues and disable PR Merge button etc

### Why are the changes needed?

Explained above

### Does this PR introduce any user-facing change?

No

### How was this patch tested?

n/a

Closes apache#28122 from kaxil/patch-1.

Authored-by: Kaxil Naik <kaxilnaik@gmail.com>
Signed-off-by: Sean Owen <srowen@gmail.com>

.asf.yaml

@@ -0,0 +1,29 @@
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements. See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.
+# The ASF licenses this file to You under the Apache License, Version 2.0
+# (the "License"); you may not use this file except in compliance with
+# the License. You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# https://cwiki.apache.org/confluence/display/INFRA/.asf.yaml+features+for+git+repositories
+---
+github:
+  description: "Apache Spark - A unified analytics engine for large-scale data processing"
+  homepage: https://spark.apache.org/
+  labels:
+    - python
+    - scala
+    - r
+    - java
+    - big-data
+    - jdbc
+    - sql
+    - spark