deprecated roms notice

[SirRGB]

Dot OS, Bianca, RR, slimroms, aosip, aokp, aex, aquari, benzo, atomic, du , fluid, firehound, forklos, xtended, pe, posp, radiant, revenge, xenon and other roms are sadly discontinued, so I suggest either removing them or just adding a note because they might no longer build if they track lineage forks.