allow multiple indexers for one collection

[T-Mike]

Hi,
Just added meilisearch to a new directus project and your work saved me a lot of time!
Because the project I work on is multilingual, I needed to be able to make an index per collection per language.
i.e : collection1_en, collection1_fr, collection2_en, collection2_fr etc...
The most logical way I could think of was change the config file structure by replacing collections key for indexes.
Let's take an example:

const config = {
  server: {
      type: "meilisearch",
      host: "http://meilisearch:7700",
      key: "mykey",
  },
  reindexOnStart: true,
  batchLimit: 100,
  indexes: {
    designer_en: {
      collectionName: 'designer',
      filter: {
          status: "published",
      },
      fields: ['id', 'some_field'],
      transform: (item, { flattenObject, striptags }) => {
        // do some things
        return item
      }
    },
    designer_fr: {
      collectionName: 'designer',
      filter: {
          status: "published",
      },
      fields: ['id', 'some_other_field'],
      transform: (item, { flattenObject, striptags }) => {
        // do some other things
        return item
      }
    }
  }
}

There are two indexes, designer_en and designer_fr and they are completely separated. Meaning you can do whatever you want with each one.

The code provided works, I did not see any bug related to it but it is not battle tested.

Hope this helps!