chore: remove old Storage abstraction layer

Removed:
- src/Storage/Contracts/StorageDriver.php
- src/Storage/RedisStorageDriver.php
- src/Storage/DatabaseStorageDriver.php
- src/Storage/StorageManager.php
- config references to storage_drivers

These classes are no longer needed after refactoring to use
Laravel's Redis facade directly via RedisMetricsStore.

The new approach is simpler, more maintainable, and leverages
Laravel's built-in features instead of custom abstractions.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: sylvesterdamgaard

config/queue-metrics.php

@@ -21,8 +21,6 @@
 use PHPeek\LaravelQueueMetrics\Repositories\RedisQueueMetricsRepository;
 use PHPeek\LaravelQueueMetrics\Repositories\RedisWorkerHeartbeatRepository;
 use PHPeek\LaravelQueueMetrics\Repositories\RedisWorkerRepository;
-use PHPeek\LaravelQueueMetrics\Storage\DatabaseStorageDriver;
-use PHPeek\LaravelQueueMetrics\Storage\RedisStorageDriver;
 
 // config for PHPeek/LaravelQueueMetrics
 return [
@@ -169,16 +167,11 @@
     | Customizable Classes
     |--------------------------------------------------------------------------
     |
-    | You can override these classes to customize the low-level behavior
+    | You can override these classes to customize the behavior
     | of the package. In most cases, you can just use the defaults.
     |
     */
 
-    'storage_drivers' => [
-        'redis' => RedisStorageDriver::class,
-        'database' => DatabaseStorageDriver::class,
-    ],
-
     'repositories' => [
         JobMetricsRepository::class => RedisJobMetricsRepository::class,
         QueueMetricsRepository::class => RedisQueueMetricsRepository::class,