[HL2] [Feature Request] Add spawnflags to all entities for difficulty settings

[sonoma-hyenaz]

Hello, I'm requesting a feature to be added to all HL2 + Episode entities which will allow level designers the ability to fine tune entity placement depending on user difficultly settings

These spawn flags would be available for every Brush entity and Point Entity

The spawn flags I would like to suggest would be

Not on Easy - Does not spawn this entity if user's difficultly setting is set to Easy
Not on Normal - Does not spawn this entity if user's difficultly setting is set to Normal
Not on Hard - Does not spawn this entity if user's difficultly setting is set to Hard

I believe this feature would be a great addition to entities and would allow level designers to have much more control and tuning with the gameplay to suit the player's skill level and enhance their experience.