Finishing civetconfig

[edemaine]

• [x] VSCode extension uses default civetconfig
• [x] CLI uses default civetconfig
• [x] unplugin should support default civetconfig, along with config override
• [ ] eslint plugin should probably do the same
• [ ] Babel plugin should probably do the same
• [ ] Gulp plugin should probably do the same
• [ ] What about ESM and Bun plugins?
• [x] Document in https://civet.dev/config

[danielbayley]

There are also the proposed potential config files, as @STRd6 mentioned in https://github.com/DanielXMoore/Civet/issues/647#issuecomment-1693542267.

Allow for parsing different config file extensions based on what modules exist in the local user project

Plus I threw together a quick PR to allow civetConfig in package.json also in #1300.