Issue #2790923 by stefanos.petrakis, jenlampton, lokapujya, alexpott, biguzis,...

Issue #2790923 by stefanos.petrakis, jenlampton, lokapujya, alexpott, biguzis, zniki.ru, dimaro, benjf, themic8, subhojit777, thtas, kpv, Noe_, Berdir, thijsvdanker, Cottser, dcam, jhodgdon: Allow + symbol in usernames