Add local avatar functionality

I vote leave this as a plugin. No need to stuff into core.

I vote this replaces gravatar.

Because there's already avatar functionality built-in, I'd say this was plugin territory...however, I think replacing gravatar with local avatars is a great idea.

I am not clearly for or against it but we must consider that Gravatar is another GDPR "headache". It is one of the third party applications/services where user data is sent. Keeping it local makes everything simpler.

That's a great point, @Chris.

Agree with the comments that this is plugin territory.

This should replace Gravatar.

Stripping out gravatar would be great, but I don't see any need to replace it because many users have no need for avatars on their sites.

Should replace Gravatar.