Pending tenants refactor (BC break)

- [BC BREAK] Make pullPendingFromPool() $firstOrCreate arg
  default to false (pullPending() is now a direct alias for
  pullPendingFromPool() with default $firstOrCreate=true)
- Resolve race conditions in pullPendingFromPool()
- Make createPending() set pending_since regardless of exceptions
- Make pullPending() accept $attributes
- Fire PullingPendingTenant from within a DB transaction
- Clarify --count arg description for CreatePendingTenants command
- Add docblock to PullingPendingTenant with a notice

src/Commands/CreatePendingTenants.php

@@ -8,7 +8,7 @@ use Illuminate\Console\Command;
 
 class CreatePendingTenants extends Command
 {
-    protected $signature = 'tenants:pending-create {--count= : The number of pending tenants to be created}';
+    protected $signature = 'tenants:pending-create {--count= : The number of pending tenants to maintain}';
 
     protected $description = 'Create pending tenants.';