feat(prettier): Add a few bells and whistle to the Prettier plugin

[Princesseuh]

The Prettier plugin was a bit limited in regards to things it could do, for instance there was not way to enforce options, which unfortunately prevent Astro (and probably Svelte and other languages who needs Prettier to format) from using the Prettier plugin.

This PR adds two properties:

• additionalOptions, allow to enforce some options of the Prettier config
• resolveConfigOptions, allow to add options when resolving (ex: disabling the cache, .editorconfig etc)

Adds a feature:

• The editor's Prettier config is now loaded and used if there's no explicit Prettier config. It goes like this: Prettier config file, if doesn't exists, editor prettier config, if doesn't exists, the base editor format settings unless ignoreIdeSettings is enabled.

Fixes an issue:

• Ignored files are now properly ignored

[johnsoncodehk]

Thanks! (I haven't really tested it, but it looks like the change isn't disruptive to users.)