hDPI texture for UI overhead

After merging https://github.com/decentraland/godot-explorer/pull/986 we covered the visual issue but some minor tech issues can be still improved:
- we are duplicating the asset if it's used both. we could track how often this happens
- we could use the not-resized (Source) asset but still using texture compression (ETC2). we could also track how many texture are in the most visited scenes and if this involes a real issue.

We should check if the effort tracking this is less than directly tackling them