This lets the TAS input code use a higher-level interface for
overriding inputs instead of having to fiddle with raw bits.
WiiTASInputWindow in particular was messy with how much
controller code it had to re-implement.

SPDX standardizes how source code conveys its copyright and licensing
information. See https://spdx.github.io/spdx-spec/1-rationale/ . SPDX
tags are adopted in many large projects, including things like the Linux
kernel.

- Use the Dolphin Icon in TAS Windows
- Prevent deformation of the stick widget (#11988)
- Improve visual appearance
- Set a reasonable minimum size

Qt/TAS: Enable antialiasing for Stick/IR widgets