Remove deprecated database.commitTransaction(), migrate to transaction.commit()

Remove the deprecated methods:
- DB.commitTransaction()
- DB.rollbackTransaction()
- DB.endTransaction()
- database.commitTransaction()
- database.rollbackTransaction()
- database.endTransaction()

Migrate to using try-with-resources and transaction.commit(), transaction.rollback()

ebean-core/src/main/java/io/ebeaninternal/api/SpiEbeanServer.java

@@ -86,6 +86,11 @@ public interface SpiEbeanServer extends SpiServer, ExtendedServer, BeanCollectio
    */
   SpiTransactionManager transactionManager();
 
+  /**
+   * End the current transaction if it is active.
+   */
+  void endTransaction();
+
   /**
    * Return all the descriptors.
    */

ebean-core/src/main/java/io/ebeaninternal/server/core/DefaultServer.java

@@ -756,16 +756,6 @@ public final class DefaultServer implements SpiServer, SpiEbeanServer {
     currentTransaction().flush();
   }
 
-  @Override
-  public void commitTransaction() {
-    currentTransaction().commit();
-  }
-
-  @Override
-  public void rollbackTransaction() {
-    currentTransaction().rollback();
-  }
-
   @Override
   public void endTransaction() {
     Transaction transaction = transactionManager.inScope();