Identify tenants by the "Origin" header (#21)

* Add origin ID MW

* Test origin ID MW

* Test origin ID MW with early identification

* Fix code style (php-cs-fixer)

* Fix PHPStan errors

* Add getDomain() to domain ID MW, simplify origin ID MW

* Fix code style (php-cs-fixer)

* Rename InitializeTenancyByOrigin to InitializeTenancyByOriginHeader

* Add onFail test

* Stop throwing the exception in getDomain()

* FIx merge

* Improve origin identification test file

* Clean up test

---------

Co-authored-by: PHP CS Fixer <phpcsfixer@example.com>

src/Middleware/InitializeTenancyByOriginHeader.php

@@ -0,0 +1,15 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Stancl\Tenancy\Middleware;
+
+use Illuminate\Http\Request;
+
+class InitializeTenancyByOriginHeader extends InitializeTenancyByDomainOrSubdomain
+{
+    public function getDomain(Request $request): string
+    {
+        return $request->header('Origin', '');
+    }
+}