Databases versions missing

Following to product team decision, a new Nuxeo version needs an upgrade path and thus will support a new version of a DB and the previous one.

For example, LTS 2019 should support postgresql 11 and 9.6.

The following pages should be updated accordingly:
https://doc.nuxeo.com/1010/nxdoc/compatibility-matrix/
https://doc.nuxeo.com/1010/nxdoc/postgresql/
https://doc.nuxeo.com/1010/nxdoc/oracle/
https://doc.nuxeo.com/1010/nxdoc/mongodb/
https://doc.nuxeo.com/1010/nxdoc/microsoft-sql-server/
https://doc.nuxeo.com/1010/nxdoc/mysql/
https://doc.nuxeo.com/1010/nxdoc/mariadb/