Adding Combined modlog

[dessalines]

Context: #2444

Must come after #5251

Notes:

• This removes all the individual modlog fetches into a single combined one, with a type_ filter.
• 17 tables joined in total, with sometimes complicated joins required to fetch the derived data.
  • For example, mod_remove_post doesn't have the modded_person_id directly on it, it needs to get it from the post.creator_id column. I've tried to keep the joins as organized and well-commented as possible.
• I've added a ton of tests, filtering different slices of all the filter types: community, post, comment, mod/admin, modded_person, and type. Its verbose, but its something we didn't have before.
• Some of the mod views had missing fields that seemed important (occasionally it was missing a community or the modded person). I've added these.
• I discovered a few errors and inconsistencies that I cleaned up.
• There are plenty of breaking changes here, which includes the types coming back for the v3 routes. I am not going to do backwards compatibility for these types. That will have to be handled by API libraries switching on v.0.19 vs v.0.20.

[dullbananas]

Suggested change

	let posts_mapped = &post_modlog.iter().filter_map(|p| {
	if let ModlogCombinedView::ModRemovePost(v) = p {
	Some(v)
	} else {
	None
	}
	});
	let posts_mapped = &post_modlog.iter().filter_map(|p| {
	if let ModlogCombinedView::ModRemovePost(v) = p {
	Some((v.mod_remove_post.removed, v.post.removed))
	} else {
	None
	}
	}).collect::<Vec<bool>>();

then replace the things below with a single assert_eq

same can be done for the other uses of filter_map

[dessalines]

K done now. I didn't like doing it because its less clear now what they're doing, and these are just tests, where clarity should be preferred over code simplification.

[dullbananas]

I think I came up with a style that's more simple and clear than the other two:

assert!(matches!(
  &post_modlog[..],
  [
    ModlogCombinedView::ModRemovePost(ModRemovePostView {
      mod_remove_post: ModRemovePost { removed: true, .. },
      post: Post { removed: true, .. },
      ..
    }),
    ModlogCombinedView::ModRemovePost(ModRemovePostView {
      mod_remove_post: ModRemovePost { removed: true, .. },
      post: Post { removed: true, .. },
      ..
    }),
  ],
));

[dessalines]

That does look much cleaner, I'll try it out.

[dullbananas]

EnumDiscriminants might help

[dessalines]

Probably not worth it to do any of the enum work. All the other combined cases just use a single char for the paging, this one's unique in that there are 17 types it needs to combine.

EDIT: I'm reverting adding strum at all because of this.