Document update SSL support

Add a new SSL section to the reference documentation to describe SSL
bundles.

See gh-34814

spring-boot-project/spring-boot-docs/src/main/java/org/springframework/boot/docs/features/ssl/bundles/MyComponent.java

@@ -0,0 +1,35 @@
+/*
+ * Copyright 2012-2019 the original author or authors.
+ *
+ * Licensed 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
+ *
+ *      https://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.
+ */
+
+package org.springframework.boot.docs.features.ssl.bundles;
+
+import javax.net.ssl.SSLContext;
+
+import org.springframework.boot.ssl.SslBundle;
+import org.springframework.boot.ssl.SslBundles;
+import org.springframework.stereotype.Component;
+
+@Component
+public class MyComponent {
+
+	@SuppressWarnings("unused")
+	public MyComponent(SslBundles sslBundles) {
+		SslBundle sslBundle = sslBundles.getBundle("mybundle");
+		SSLContext sslContext = sslBundle.createSslContext();
+		// do something with the created sslContext
+	}
+
+}