Currently only attached to the Anti Aliasing of the solid mode of the
viewport. But eventually we could add other options here. Quality
setting can be found in the System tab of the userpref.
The slider goes from No Antialiasing (0.0 - 0.1) to FXAA (0.1 - 0.25) to
TAA8 (0.25 - 0.6) to TAA16 (0.6 - 0.8) to TAA32 (0.8 - 1.0)