Implement "Filter this post" from web UI

[BDGreyson]

Is your feature request related to a problem? Please describe. The web UI has the context menu option "Filter this post" which allows a user to filter and thus hide an individual post, for example if a post isn't properly content-warned but you don't want to block/mute the whole account, especially as it would also remove its reappearance through Boosts.

Describe the solution you'd like It would be nice if this option would also be present in Pachli's post-context-menu, as the current filter view is based on word filtering.

Describe alternatives you've considered It's not really a totally important thing, so, the alternative is just "dealing with it", I don't need it very often, but it would bring Pachli closer to web functionality.