[WIP] Added automatic DPI scaling to editor

[adriengivry]

Description

This PR enables the following ImGui config flags:

• ImGuiConfigFlags_DpiEnableScaleViewports
• ImGuiConfigFlags_DpiEnableScaleFonts

Note: ImGui mentions:

ImGuiConfigFlags_DpiEnableScaleViewports= 1 << 14,  // [BETA: Don't use] FIXME-DPI: Reposition and resize imgui windows when the DpiScale of a viewport changed (mostly useful for the main viewport hosting other window). Note that resizing the main window itself is up to your application.
ImGuiConfigFlags_DpiEnableScaleFonts    = 1 << 15,  // [BETA: Don't use] FIXME-DPI: Request bitmap-scaled fonts to match DpiScale. This is a very low-quality workaround. The correct way to handle DPI is _currently_ to replace the atlas and/or fonts in the Platform_OnChangedViewport callback, but this is all early work in progress.

So we might need to do more investigation whether this is the right approach.

Edit: It seems like these config options do not exist anymore on ImGui's latest.
Edit 2: These options are now in ImGuiIO, as ConfigDpiScaleFonts and ConfigDpiScaleViewports

To-Do:

• Fix some buttons don't scale properly
• Validate on a variety of screen sizes

Related Issue(s)

Fixes #(issue number)

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Screenshots/GIFs

MacBook Pro M1 (Asahi Linux) 3456x2160

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