Update databases/mysql-connector-java to 8.0.13

This now requires Java 1.8+

Repo-copy the orgiginal port to databases/mysql-connector-java51 to
provide continued support for Java 1,6 and 1.7 users. Hook up to the
tree.

Summary of Changes: https://insidemysql.com/connector-j-8-0-11-the-face-for-your-brand-new-document-oriented-database/
ChangeLogs: https://dev.mysql.com/doc/relnotes/connector-j/8.0/en/