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/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 = [];