Feature: Add func_light brush entity

[JVGRYT]

Which component should be improved?

Entity

Describe your suggestion

Essentially what I'm suggesting is functionally a texlight that is customisable within hammer itself, via a brush entity.
Basically, you create a brush with the trigger texture, turn it into a brush entity, and select func_light or alternatively func_texlight. This entity's keyvalues would be similar to a regular light entity, the difference being you can choose which faces to light.

Also, being an entity, it would be possible to name this light and turn it on and off.
Another possibility would be allowing this entity to generate dynamic lighting as well as static, though this may significantly affect performance so it may not be plausible to implement this.