Default dupe filter blacklists

[roachcord3]

There are a few very common cases where people will merge dupes and introduce nonsense, such as tagging an image both with meta:censored and meta:uncensored, or combining rating:safe and rating:explicit (where the hell does this person work?) I think there should be a conservative list of tags that are blacklisted by default in the "this is better" dupe merge option, to prevent new users from committing things like this without there being a good reason for it.

I welcome the community to suggest alterations to this list, this is just an initial proposal:

• all rating: tags
• censored, medium:censored, and meta:censored (and the uncensored counterparts)
• your filename sucks/your filenames suck

[roachcord3]

A user brought up the concept of a default blacklist on all imports. While I agree that we should add one, I think it would need to have a different set. For example, it's reasonable to parse and import the various censored tags, but we'd probably want to blacklist things like https: tags (aka broken parser garbage.) Should that be a separate issue, since it'd definitely be a different set of tags? (Though, it might just be a subset...)

[Zweibach]

Given that we now have repository tag filters, aka PTR tag blacklist, it'd be nice if the client respected that when doing dupe filter tag actions on the PTR tag service.