Add basic embedded overrides support

[Sec-ant]

This is a preliminary attempt to add option overrides support for embedded languages, see #16 (comment)

• Add a new option embeddedOverrides. This option accepts a stringified json string or an absolute json file path as its value.
• The value should be in the following form, an example 👇:

  [
    {
      "identifiers": [
        "sql"
      ],
      "options": {
        "keywordCase": "lower",
        "indentStyle": "tabularRight"
      }
    },
    {
      "identifiers": [
        "mysql"
      ],
      "options": {
        "keywordCase": "upper"
      }
    }
  ]

Note: Not all options are supported for overriding. Check the interface definition:

export interface EmbeddedOverride {
  identifiers: AutocompleteStringList<EmbeddedDefaultIdentifier[]>;
  options: Omit<
    // native prettier options
    Omit<Options, keyof PrettierPluginEmbedOptions> &
      // prettier-plugin-embed options
      // except for "embedded<Language>Identifiers"
      // and global options
      // (they should be set globally, not in overrides)
      Omit<
        PrettierPluginEmbedOptions,
        | keyof PrettierPluginGlobalOptions
        | ReturnType<typeof makeIdentifiersOptionName<EmbeddedLanguage>>
      >,
    // these options are used in `printDocToString`,
    // we cannot override them because plugins can only affect ast and doc generation at most
    // check: https://github.com/prettier/prettier/blob/7aecca5d6473d73f562ca3af874831315f8f2581/src/document/printer.js
    | "printWidth"
    | "endOfLine"
    | "useTabs"
    | "tabWidth"
    // some other options we don't want to expose to the users or don't make sense to override
    | "parser"
    | "filepath"
    | "embeddedLanguageFormatting"
    | `__${string}`
  >;
}