Optimize workspace builder resource dump format

[vaterlaus]

Currently the resource dump contains a lot of extraneous content that doesn't actually add any information and could be stripped out to greatly reduce the size of the resource dump file. Examples are:

• fields with null values
• fields with empty dictionary/list values

Also, when I looked at current dumps after recent changes it seems like the resource dump is including YAML tags/references, which I thought I had removed, so I think there's some regression there that I need to look into.

[vaterlaus]

When the resource dump/load feature was added recently the esource dump format is now the YAML serialized form of the resource registry, which can then be deserialized to reconstruct the registry from the dump file. So the dump format now contains YAML tags/references, so that part of the description is no longer valid. It's still the case that it includes fields whose value is null or empty arrays/objects, which seems like they could be pruned from the dump to simplify and reduce the dump size without substantively changed the content. Although I'm a little worried that that could subtly affect the deserialized content when the dump file is reloaded, so we'd need to do some testing that it didn't affect the evaluation of the generation rules. Given that caveat I would deprioritize this ticket, especially because I think the existence of the empty content doesn't dramatically increase the size of the dump file and it's really only a developer-facing feature so it's ok if it's not super optimized/efficient.