Write on-the-fly docker image for Oracle

The image would extend from one of those available in the internal catalog.
If not viable, official scripts from oracle to build images are available here:
https://github.com/oracle/docker-images/tree/master/OracleDatabase

Target versions are 11g, 12c one image per version.

Database can then be initialized.

More details on Nuxeo specifics here:
https://doc.nuxeo.com/nxdoc/oracle/

Target repository:
https://github.com/nuxeo/nuxeo-tools-support-priv/tree/master

Target folder:
docker/images/oracle

The DB version will then be handled in compose files through a ORACLE_VERSION variable (with a default value matching the Nuxeo version).

Add compose file for simple Nuxeo + DB scenario.