[WIP] Update jfr-connection module to follow style guide

jfr-connection/src/main/java/io/opentelemetry/contrib/jfr/connection/JfrConnectionException.java

@@ -37,7 +37,7 @@
  *       This cause indicates a bug in the io.opentelemetry.contrib.jfr.connection package code.
  * </dl>
  */
-public class JfrConnectionException extends Exception {
+public final class JfrConnectionException extends Exception {
 
   private static final long serialVersionUID = 7394612902107510439L;
 

jfr-connection/src/main/java/io/opentelemetry/contrib/jfr/connection/PredefinedConfiguration.java

@@ -17,7 +17,7 @@
  * option of the JVM option 'StartFlightRecording', for example {@code
  * -XX:StartFlightRecording:settings=default.jfc}.
  */
-public class PredefinedConfiguration implements RecordingConfiguration {
+public final class PredefinedConfiguration implements RecordingConfiguration {
   private final String configurationName;
 
   @Override

jfr-connection/src/main/java/io/opentelemetry/contrib/jfr/connection/Recording.java

@@ -21,7 +21,7 @@
  * @see <a
  *     href="https://docs.oracle.com/en/java/javase/11/docs/api/jdk.jfr/jdk/jfr/Recording.html">jdk.jfr.Recording</a>
  */
-public class Recording implements AutoCloseable {
+public final class Recording implements AutoCloseable {
 
   /**
    * A {@code Recording} may be in one of these states. Note that a {@code Recording} is no longer

jfr-connection/src/main/java/io/opentelemetry/contrib/jfr/connection/RecordingOptions.java

@@ -41,7 +41,7 @@
  * it does mean that the Builder needs to validate the args and potentially throw
  * IllegalArgumentException. String makes the overall code so much simpler.
  */
-public class RecordingOptions {
+public final class RecordingOptions {
 
   private static final String NO_LIMIT = "0";