feat: update filter to allow multiple RGB values to be configured for a single instance of the filter

[thaMANSTA]

• I've been playing a bunch of PS1 lightgun games, and capturing using OBS on an M1 Mac Mini
• adding multiple instances of the filter to filter the different flash colours is cumbersome
• for Lethal Enforcers 1, "tint" the scene red when you get hit, causing secondary flashing in addition to the white flashes when you shoot
• to get around this, I was taking screenshots of "flashing" frames, and adding multiple filters for all the shades of red that were flashing on screen
• unfortunately, adding many flash filters causes FPS issues
• solution is to update the filter to support multiple RGB values for the same filter instance, which should be much more performant than multiple filter instances