Use project's prettier config when basePath is provided

[jaredmcateer]

When providing the basePath in the Vuedc Options we infer the tsconfig.json project for better type inference (especially in regards to mixins) but we could also look for a prettier config file and use that instead of the default config used by Vuedc. I would like to keep this limited to an assumption based on this option rather than providing yet another separate option in order to keep complexity down to a "quick" vs "featureful" experience. When it comes down to it the end user can always run the output through their own projects formatter anyways.