FR: Add ability to resize and normalize icons during import.

[Nek-12]

Some designers export icons in weird sizes like 45x45 or 17x21. While we developers wage war against such crimes, we also have to cope with it by resizing icons manually on Figma to 24x24 and then exporting them through Valkyrie. If possible, add an option to resize an icon or all icons in a pack (both default* size options and the dimensions of the vector path) during import to a defined value, 24.dp by default, so that everything devs are doing on Figma can be automated:

1. Icons have 24.dp default size
2. Icons have 24x24 viewport and are uniformly scaled to match it
3. Icons are resized to fit the bounding box with no padding
4. Icons are centered in the viewport

Options 3 and 4 should be configurable if they cause problems, or can be omitted if they are take too much work

[err09r]

In addition, it would be great if there was an option to specify the desired icon size to which the input icons will be converted. For example, I have a 1024x1024 SVG icon pack and want it resized according to my app's UI guidelines (24x24). Also it seems to be a good option due to optimization reasons.