…HP-CMSIG#666)

Currently it is not possible to create a reusable ReindexProvider as all
ReindexProviders require to implement a static method `public static
function getIndex(): string` we should get rid of them so people can
create ReindexProviders which are reusable and just configurable by
there constructor.

This also add possibility to wrap / decorate ReindexProviders easier,
which we require for ODM (PHP-CMSIG#81 PHP-CMSIG#661).

## BC Breaks

The `ReindexProviderInterface` and `getIndex` method is not longer
static and the interface was renamed to `StaticReindexProviderInterface`
as in a `DynamicReindexProviderInterface` without getIndexName method
will be added in upcoming PR:

```diff
-class YourClass implements ReindexProviderInterface {
+class YourClass implements StaticReindexProviderInterface {
    // ...

-   public static function getIndex(): string
+   public function getIndexName(): string
    {
        return 'test';
    }
}
```

If you need to support 0.12 and 0.13 the same time you can implement
both methods and keep using the deprecated ReindexProviderInterface
until 0.14 or 1.0:

```diff
class YourClass implements ReindexProviderInterface {
    // ...

    public static function getIndex(): string
    {
        return 'index';
    }

+   public function getIndexName(): string
+   {
+        return self::getIndex();
+   }
}
```

fixes PHP-CMSIG#615