[WIP] Dialog to view depth maps

[ChemicalXandco]

Description

This PR makes it easier to view depth maps - currently, the only way to view them is to drag and drop from the cache folder

Features list

• List of depth map files
• 2D viewer for the selected file
• Ability to load depth map into 3D viewer within Meshroom
• Filter depth maps by type
• Make feature overlay work properly on the depth map file on 2D viewer

Implementation remarks

• Dialog is opened by double-clicking either a DepthMap or DepthMapFilter node
• Refresh button allows new depth maps to be viewed while the node is running

[fabiencastan]

@ChemicalXandco That's an interesting feature!
It would be good to avoid the popup window and directly open the depthmap in 2D/3D viewers based on the selected images as it's done for features visualization and camera view.

[natowi]

Icon proposal