Add fractional UI scaling

[Tractix]

Describe the request

I have a 1440p display and the sweet-spot for UI scaling for me would be a 2.5 but that's currently not possible.

My suggestion is that fractional scaling is added so you can set the scaling to 1, 1.5, 2, 2.5, etc.
Perhaps even 1, 1.25, 1.5, 1.75, 2, etc. but I don't know if such granularity is necessary.