Improve documentation wrt initialization state of returned objects

[dominikl]

It's not clear to which level objects retrieved via the various getter methods are actually initialized. Some methods return a fully initialized object (e. g. a DatasetData object with the list of ImageData loaded), some don't (e. g. only a flat DatasetData object with no images or annotations loaded). This should at least be stated cleary in the methods docs.
(See comment on “Could not roll back JDBC transaction”)

[imagesc-bot]

This issue has been mentioned on Image.sc Forum. There might be relevant details there:

https://forum.image.sc/t/could-not-roll-back-jdbc-transaction/51774/4

[imagesc-bot]

This issue has been mentioned on Image.sc Forum. There might be relevant details there:

https://forum.image.sc/t/get-dataset-id-from-image-id-in-script-from-omero/54293/2

[imagesc-bot]

This issue has been mentioned on Image.sc Forum. There might be relevant details there:

https://forum.image.sc/t/omero-java-api-get-user-configured-metadata-for-image-id/56730/6

[imagesc-bot]

This issue has been mentioned on Image.sc Forum. There might be relevant details there:

https://forum.image.sc/t/size-of-child-objects-from-parent-dataset-plate-returns-1/80019/2