Remove dependency on java.activation

[jjspiegel]

SODA has a small dependency on java.activation:

./src/oracle/soda/rdbms/impl/OracleDocumentImpl.java:
import javax.activation.MimeType;

./src/oracle/soda/rdbms/impl/OracleDocumentImpl.java:
import javax.activation.MimeTypeParseException;

This Java EE module is deprecated for removal in Java 9 and will be removed from the jdk in Java 11.
http://openjdk.java.net/jeps/320

Can we remove this dependency from soda?