Make convenience helpers in Log/LogRecord

[ormsbee]

This would be for determining whether change are:

• side-effects
• pure side-effect
• direct changes
• indirect changes
• direct publish
• indirect publish
• indirectly affected by publish
• soft-delete

That way we can keep terminology more consistent, and not have calling code comparing version_nums to each other to try to figure out what each of those things means.

[bradenmacdonald]

Based on my experience implementing events, it would also be helpful to differentiate "un-delete" (reverting a soft delete) from "create", since both just show up as (old_version=None, new_version=X) but are best handled differently.

[bradenmacdonald]

Do you think this is something to prioritize for the event data before Verawood? Or are you thinking just the DraftChangeLog etc. but not the events?

[ormsbee]

I think it's useful to have at both layers, but can be added post-Verawood.