[9.x] Add command delete-all-indexes, update scout:index to allow FQCN and apply filterable on SoftDeletes

[kichetof]

This PR add some new features for Meilisearch:

• scout:index accept a FQCN as name argument.
• Apply filterable attribute on __soft_deleted when Model use SoftDeletes at index creation.
• Added a new command to delete all indexes (only Meilisearch support it).

---

With this addition, your Scout.php config file will not look like this crazy repetition:

'meilisearch' => [
    'host' => env('MEILISEARCH_HOST', 'http://localhost:7700'),
    'key' => env('MEILISEARCH_KEY', null),
    'index-settings' => [
        Model_A::class => [
            'filterableAttributes' => ['__soft_deleted'],
        ],
        Model_B::class => [
            'filterableAttributes' => ['__soft_deleted'],
        ],
        Model_C::class => [
            'filterableAttributes' => ['__soft_deleted'],
        ],
        Model_D::class => [
            'filterableAttributes' => ['__soft_deleted'],
        ],
        // ....
        Model_Y::class => [
            'filterableAttributes' => ['__soft_deleted'],
        ],
        Model_Z::class => [
            'filterableAttributes' => ['__soft_deleted'],
        ],
    ],
]

[taylorotwell]

Made some changes to this. I removed the auto-addition of __soft_deleted as that was not consistently carried through to sync-index-settings command which felt inconsistent.

I also actually registered the command in the service provider, which raised some concern to me as the command would not have been invokable otherwise and therefore I'm not sure how it could have been tested even manually? Did you try to run this code?

[taylorotwell]

Verified this all works on my Sail installation. Thanks.

[kichetof]

Thanks for merging it! (delete-all-indexes come from my own custom command and I totally forgot to commit provider, thanks!)

I'll think over the weekend how to add __soft_deleted out of the box. I've an idea to add it on sync-index-settings command, let's see after a break :)