expand logging for draft edits

[pameyer]

Short version - change log for draft datasets could use some additional information.

Longer version - UpdateDatasetVersionCommand (and possibly CreateDatasetVersionCommand) provide information about which dataset version was changed, and who changed it - but there doesn't appear to be accessible information about what was changed. Not sure if it makes more sense to add this to the action log record info field, or add a new logger / log file.

[pdurbin]

Related: #1002

[pameyer]

@pdurbin Thanks - that is closely related (aka #1002 would eliminate the need for this).