Reference Image Improvements

[TheLsbt]

Please Note that this pull request is not ready This pull request aims to improve reference images and how they are handled in Pixelorama

Changes and updates

Internal

• Made it so that all reference images nodes (Sprite2D's) are stored under ReferenceImages (res://src/UI/Canvas/Canvas.tscn).
• Improved the silhouette shader to allow for color clamping.
• Added saving and loading of the rotation, color_clamping
• Changed "silhouette" to "monochrome"

UI

• Set "Reference Images/Label" autowrap to "word" because the panel never wanted to shrink.
• All ReferenceImages are edited from a single ui and not individual cards.
• Added ui for modulating the silhouette.
• Added a rotation option.
• Made the button that opens the ReferenceImage a actual Button since LinkButton's words cannot be "cut of".

TODO

• [ ] Add info to tell the user how the ReferenceImage is being transformed such as a label
• [ ] Give users info on how to transform (The modifier keys)
• [ ] Make the Gizmo more user friendly by adding physical buttons to change Move, Rotate, Scale
• [ ] Add a quick menu (A menu that can open with a shortcut to quickly select a ReferenceImage
• [ ] This "quick menu" would also be able to summon the actual Reference Panel when the whole DockContainer
• [ ] plugin get sorted out. It would be nice for users to also quickly edit "color options" like Modulate, Opacity, etc.
• [ ] Add a option to hide all reference images.