Add TenantConfigBootstrapper, deprecate Feature implementation

The feature was pretty much a soft-bootstrapper -- it listened
to both Bootstrapped and Reverted. Bootstrappers have a few more
protections in terms of error handling and safe reverting, so there's
no point in (badly) re-implementing bootstrapper functionality within
TenantConfig just so it could be a Feature.

Going forward, all Features should be things that are mostly agnostic
of the tenant state, and especially they should not use bootstrapped/
reverted events. Bootstrappers are simply more appropriate and safe.

src/Bootstrappers/TenantConfigBootstrapper.php

@@ -0,0 +1,54 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Stancl\Tenancy\Bootstrappers;
+
+use Illuminate\Config\Repository;
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Support\Arr;
+use Stancl\Tenancy\Contracts\TenancyBootstrapper;
+use Stancl\Tenancy\Contracts\Tenant;
+
+class TenantConfigBootstrapper implements TenancyBootstrapper
+{
+    public array $originalConfig = [];
+
+    /** @var array<string, string|array> */
+    public static array $storageToConfigMap = [
+        // 'paypal_api_key' => 'services.paypal.api_key',
+    ];
+
+    public function __construct(
+        protected Repository $config,
+    ) {}
+
+    public function bootstrap(Tenant $tenant): void
+    {
+        foreach (static::$storageToConfigMap as $storageKey => $configKey) {
+            /** @var Tenant&Model $tenant */
+            $override = Arr::get($tenant, $storageKey);
+
+            if (! is_null($override)) {
+                if (is_array($configKey)) {
+                    foreach ($configKey as $key) {
+                        $this->originalConfig[$key] = $this->originalConfig[$key] ?? $this->config->get($key);
+
+                        $this->config->set($key, $override);
+                    }
+                } else {
+                    $this->originalConfig[$configKey] = $this->originalConfig[$configKey] ?? $this->config->get($configKey);
+
+                    $this->config->set($configKey, $override);
+                }
+            }
+        }
+    }
+
+    public function revert(): void
+    {
+        foreach ($this->originalConfig as $key => $value) {
+            $this->config->set($key, $value);
+        }
+    }
+}

src/Features/TenantConfig.php

@@ -13,6 +13,9 @@ use Stancl\Tenancy\Contracts\Tenant;
 use Stancl\Tenancy\Events\RevertedToCentralContext;
 use Stancl\Tenancy\Events\TenancyBootstrapped;
 
+// todo@release remove this class
+
+/** @deprecated Use the TenantConfigBootstrapper instead. */
 class TenantConfig implements Feature
 {
     public array $originalConfig = [];