Feature request: graphics device capabilities checker

[teunbrand]

This feature request follows up on discussion in #5299 (comment).

To summarise: if ggplot2 is considering taking up newer graphics features, such as patterns, we'd need to check if the device is capable of using these features. Several extension developers also expressed interest in having ggplot2 export such a checker.

@trevorld has released such a checker here that is free to copy and/or adapt due to the 'unlicence' licence.

There are a few hurdles that makes implementing this checker more complicated:

• {svglite} and {ragg} don't report several features that are implemented in dev.capabilities().
• IIRC {vdiffr} uses a variant of {svglite} that uses the same device name, but does not support patterns for stability reasons.