Update pkgdown site

[phdjsep]

Hello! Huge fan of duckdb and R. Wanted to make some small improvements to the pkgdown site and set the seeds for future vignette contributions.

I've done the following in this PR:

• Added an index.md file to separate Github README presentation from pkgdown site
• Moved pkgdown.yml to pkgdown/ folder; added description to the home page
• Create a "Get Started" page; Copied from duckdb Documentation for now
• Added a switchable (light/dark) parameter in the pkgdown yml
• Added a hex logo

[krlmlr]

Thanks. CI/CD is failing:

Perhaps the ‘VignetteBuilder’ information is missing from the DESCRIPTION file?

I also quite enjoy the current vignette-less state: with a vignette, R CMD build needs to temporarily install the package, and this takes a long time here. Can we achieve a similar result with pkgdown articles that are not recognized by R CMD build , or perhaps with just .github/README.md and README.Rmd ?

Does the hex logo need to be over 2000 pixels wide? Is there perhaps a smaller version?

[phdjsep]

Gosh. I see your point. I'll remove the Vignette, but keep the split readme and smaller hex.