Add JavaBeans Activation Framework API to LICENSE.txt

When I compile HBase master trunk against Hadoop trunk

$ mvn package -Dhadoop.profile=3.0 -Dhadoop-three.version=3.3.0-SNAPSHOT -DskipTests=true

, it fails to compile:

[INFO] — maven-enforcer-plugin:3.0.0-M1:enforce (check-aggregate-license) @ hbase-shaded-client —
[WARNING] Rule 0: org.apache.maven.plugins.enforcer.EvaluateBeanshell failed with message:
License errors detected, for more detail find ERROR in
/Users/weichiu/sandbox/hbase/hbase-shaded/hbase-shaded-client/target/maven-shared-archive-resources/META-INF/LICENSE

Checking the error in the file, I saw

–
This product includes JavaBeans Activation Framework API jar licensed under the CDDL/GPLv2+CE.

CDDL or GPL version 2 plus the Classpath Exception
ERROR: Please check ^^^^^^^^^^^^ this License for acceptability here:

https://www.apache.org/legal/resolved

If it is okay, then update the list named 'non_aggregate_fine' in the LICENSE.vm file.
If it isn't okay, then revert the change that added the dependency.

More info on the dependency:

<groupId>javax.activation</groupId>
<artifactId>javax.activation-api</artifactId>
<version>1.2.0</version>

It looks like the dependency was added in HADOOP-15775. ajisakaa tasanuma0829 could you check? We'll need to understand the license of this library

https://github.com/javaee/activation/blob/master/LICENSE.txt