New Gamerule: Pacifist Mobs in Survival

"I want a new gamerule like /gamerule passiveHostiles true. When active, hostile mobs (like Blazes, Zombies) spawn normally in the world, but they don't attack the player unless attacked first (like in Creative mode). This would be amazing for players who want to see mobs and play Survival mode, but without the constant danger or pressure.