Add package-info.java for generating javadoc and source jar file

[kazuki43zoo]

I add package-info.java for generating javadoc and source jar file at starter projects. The maven.javadoc.failOnError option need for generate the javadoc jar file with only package-info.java file.

NOTE: We need to generate javadoc and source jar files for deploying to Maven Central repository.

[coveralls]

coverage: 97.715%. remained the same
when pulling bfb649c on kazuki43zoo:support-javadoc-and-source-jar-on-starter
into f98cb0b on mybatis:master.

[hazendaz]

Saw the failure last night. Typically those are on source side for all package files but with tests that have no source side they go on test side. Hopefully that will resolve issue for you.