Change missing extracted files to warnings. Fix plasma scripting config key page. Tabify config.toml and gitignore extracted files.

I added alert boxes when the imported file is missing. Eg: http://localhost:1313/docs/kauth/using_kauth/

I also fixed the Plasma Scripting config key list. The hugo documentation mentions the file needs to be in data/ not _data/. I added a few code tags too.

• https://gohugo.io/templates/data-templates/#example-jaco-pastorius-solo-discography
• http://localhost:1313/docs/plasma/scripting/keys/

I also tabified config.toml and added the generated folders to .gitignore.