[Feature] Block user

As a user, I would like to have the ability to block users from interacting with my posts, at least in terms of commenting. Currently, when I mute a user, only on my logged-in view the comments are hidden, but the public can still see it.

The basic idea was also explained here: https://peakd.com/poll/@steemitblog/follow-up-poll-expanding-mute

However, it was "planned" to "enhance" the mute transaction, instead of adding a new transaction block. I think having a separate transaction for publically "blocking" someone from interacting is better than just changing the mute function. They both have their functions and not every user should be publically hidden on my posts when muted.

And ofc, the blocking is really just filtering on hivemind.