Restore SQL DDL to Oracle Express Edition (Oracle XE)

[isedwards]

This issue is a proxy for: https://github.com/opencdms/met-office-midas/issues/1
(Allowing ZenHub to track and record story points).

The majority of the complexity of this task is captured in a separate issue (allowing separate story point and time tracking): https://github.com/opencdms/opencdms-test-data/2