Fans have been left waiting almost a quarter of a century for a sequel, but now at last Paramount Studios has released an action-packed three-minute “Gladiator 2” trailer, four months before the blockbuster’s scheduled cinema release. The trailer, teasing many bloody battle scenes in the Roman Colosseum, features a mounted rhinoceros and attacking warships, setting an intense tone for the sequel to the original 2000 film. Irish actor Paul Mescal of “Normal People” fame has trained hard to build muscles for his gladiatorial role in the upcoming film, directed by Ridley Scott. As the lead actor,…