Allow read/write enabled on runtime imported textures

[cpetry]

Is your feature request related to a problem? Please describe. I need to read and be able to adjust textures after a runtime import.

Describe the solution you'd like Add an option in the ImportSettings

Describe alternatives you've considered

Additional context I use gltf files as a basis for my project internal materials and textures. These need to be loaded in runtime and could grow over time while the user adds more materials/textures