[9.x] Support Meilisearch index settings

[driesvints]

This PR adds support for Meilisearch's index settings:

https://docs.meilisearch.com/learn/configuration/settings.html
https://docs.meilisearch.com/reference/api/settings.html

Through a new settings key on the scout.meilisearch config option, users will be able to define all the settings they need for their model indexes. These settings will be synced when the index is manually created through the scout:index command or whenever models get updated through the engine or when they use the new scout:sync-settings command.

'meilisearch' => [
    'host' => env('MEILISEARCH_HOST', 'http://localhost:7700'),
    'key' => env('MEILISEARCH_KEY', null),
    'settings' => [
        'users' => [
            'filterableAttributes'=> ['id', 'name', 'email'],
        ],
    ],
],

[driesvints]

@mmachatschek I'd appreciate a review here if you're up for it : )

[mmachatschek]

The code looks good to me 👍 I'm just concerned about one change:

[mmachatschek]

@driesvints this is a nice addition. thats basically the same code that I use in my environment. I didn't test your code but it looks rock solid 👍

#669 (comment)

[driesvints]

Thanks!

[Bjornftw]

This is for everyone who is trying to add Meilisearch settings with @driesvints comment:

The settings key is renamed to index-settings instead of settings. settings will give you a No index settings found for the "meilisearch" engine. error.

Updated version:

'meilisearch' => [
    'host' => env('MEILISEARCH_HOST', 'http://localhost:7700'),
    'key' => env('MEILISEARCH_KEY', null),
    'index-settings' => [
        'users' => [
            'filterableAttributes' => ['id', 'name', 'email'],
        ],
    ],
],