don't multiply canvas size with devicePixelRatio

## Use Case

Some users on older hardware experience slowness.
Hypothesizing that rendering fewer canvas pixels can help. This goes on the assumption that visual display resolution would be high enough without needing every native device pixel.

## Solution

Allow an option (advanced settings) to reduce canvas's internal rendering size by devicePixelRatio. This is a threejs webgl configuration setting. See https://github.com/allen-cell-animated/vole-core/blob/ccf761a520b01bb91a61a5edcfcc2cea3549b784/src/ThreeJsPanel.ts#L171
Test performance increase on low end and high end laptops for both macos and pc. Also test visual quality difference. If we feel good about it on all devices, then we can default to the lower res setting and get performance win.

## Alternatives

Bonus: detect low performance (how??) and automatically switch canvas resolution.