[feat] Regex-based post filtration #273

The idea

Users should have an option to create filters for posts that use regex, for more precise post filtration. Probably should be separate from word-based filtration so less technically-inclined users (or, frankly, people who just can't be assed to use regex in general) aren't forced to figure out how regex works and to rework all their existing filters.

The reasoning

I've had issues with some filters of mine hitting false positives before that would be fixed by being able to use regex filtration instead, with one notable example being my filter for RT @, intended to filter out crossposted retweets, but instead I've had some instances of posts with people typing out a word that ends in -rt and then @ mentioning someone being filtered out this way. I've had other similar things happen with other filters of mine, but I'm admittedly drawing a blank on any other examples. Unsure if I've heard anyone else mention wanting this, but certainly this has to have been a problem some other people have encountered before.

Have you searched for this feature request?

I have double-checked and have not found this feature request mentioned anywhere.
This feature is related to the pleroma-fe Akkoma frontend specifically, and not the backend.

Probably should be separate from word-based filtration so less technically-inclined users (or, frankly, people who just can't be assed to use regex in general) aren't forced to figure out how regex works and to rework all their existing filters.

alternatively we could just have special syntax to denote that a line's a regex, like elixir's ~r/whatever/

pretty sure this is going to have to be in the backend, mutes aren't just a frontend hide

gonna hard-veto this ever going into the backend, no way running user-generated regex is a good idea