[Feature] Change size of interface elements

On 4K monitors or other high dpi or high resolution monitors, some elements of the interface (mostly buttons) can look very small.

Here are the 3 areas that are the most problematic for me :

I see 2 ways to approach this:

• a global interface size setting
• separated settings for different types of interface elements

Also, if the icons are in a vector format, the settings could use a custom value rather than predefined values.

In fact, all of the above could be implemented, as Blender did for example, but I'd be fine with any approach taken, as long as I can make those buttons larger.