Remove Light Sources Trigger: Add option to re-enable light sources

[maddie480]

This is needed for the beginner "heart side". Rue's part uses Remove Light Sources Trigger, but light sources need to be turned back on after passing it.

This is ... pretty much a refactor of the trigger D:

• instead of using a session flag, the trigger uses mod session
• instead of handling level exit to turn on/off hooks, the trigger checks mod session. The hooks are made to just "pass through to vanilla" when light sources are not disabled.
• instead of making bloom invisible and removing lights, the alpha of bloom/light points is multiplied by a float that fades to 0 when light sources are disabled, 1 when they are enabled.

[Cruor]

Looks good to me 👍