Rename controller namespaces: drop V1 prefix, clarify roles

V1/Admin     -> Company       (company-scoped controllers)
V1/SuperAdmin -> Admin        (platform-wide admin controllers)
V1/Customer  -> CustomerPortal (customer-facing portal)
V1/Installation -> Setup      (installation wizard)
V1/PDF       -> Pdf           (consistent casing)
V1/Modules   -> Modules       (drop V1 prefix)
V1/Webhook   -> Webhook       (drop V1 prefix)

The V1 prefix served no purpose - API versioning is in the route prefix
(/api/v1/), not the controller namespace. "Admin" was misleading for
company-scoped controllers. "SuperAdmin" is now simply "Admin" for
platform administration.

app/Http/Controllers/CustomerPortal/Auth/LoginController.php

@@ -0,0 +1,45 @@
+<?php
+
+namespace App\Http\Controllers\CustomerPortal\Auth;
+
+use App\Http\Controllers\Controller;
+use App\Http\Requests\Customer\CustomerLoginRequest;
+use App\Models\Company;
+use App\Models\Customer;
+use Hash;
+use Illuminate\Http\Response;
+use Illuminate\Support\Facades\Auth;
+use Illuminate\Validation\ValidationException;
+
+class LoginController extends Controller
+{
+    /**
+     * Handle the incoming request.
+     *
+     * @return Response
+     */
+    public function __invoke(CustomerLoginRequest $request, Company $company)
+    {
+        $user = Customer::where('email', $request->email)
+            ->where('company_id', $company->id)
+            ->first();
+
+        if (! $user || ! Hash::check($request->password, $user->password)) {
+            throw ValidationException::withMessages([
+                'email' => ['The provided credentials are incorrect.'],
+            ]);
+        }
+
+        if (! $user->enable_portal) {
+            throw ValidationException::withMessages([
+                'email' => ['Customer portal not available for this user.'],
+            ]);
+        }
+
+        Auth::guard('customer')->login($user);
+
+        return response()->json([
+            'success' => true,
+        ]);
+    }
+}