refactor(prettier): simplify plugin options

[johnsoncodehk]

• Renamed languages option to documentSelector.
• The following options have been removed and are now handled through a getFormattingOptions option:
  • ignoreIdeOptions
  • useIdeOptionsFallback
  • additionalOptions
  • resolveConfigOptions
• Removed prettier and getPrettier options. Now, the prettier instance or getter must be passed as the first parameter. The plugin no longer attempts to require('prettier') on its own.
• Removed allowImportError option. If the getter returns undefined, the plugin simply does nothing. The getter is responsible for reporting errors.
• Added a isFormattingEnabled option to handle fileInfo.ignored confition.

[Princesseuh]

Looks great to me! Tried the Astro PR as well and it worked.