Update the WOFS query function to query the AGDC database for WOFS datasets

[simonoldfield]

Currently the WOFS datasets are being queried from the filesystem as they have not yet been ingested into the AGDC database.
Once they have been ingested the query method should be updated to use the database records.

[simonoldfield]

I've updated the code to query the database for WOFS datasets but due to an issue in the WOFS ingest the WOFS datasets are not being associated with the correct acquisition record.

See issue #83.

Once re-ingested I'll re-run my tests.