feat: implement External system (API) controller with key management

backend/app/Http/Controllers/ExternalApiController.php

@@ -0,0 +1,49 @@
+<?php
+
+namespace App\Http\Controllers;
+
+use App\Models\User;
+use Illuminate\Http\Request;
+use Laravel\Sanctum\Sanctum;
+
+class ExternalApiController extends Controller
+{
+    public function all_keys(Request $request)
+    {
+        $tokens = Sanctum::$personalAccessTokenModel::with('tokenable')->get();
+
+        $tokens = $tokens->map(fn($token) => [
+            "id" => $token->id,
+            "name" => $token->name,
+            "created_at" => $token->created_at,
+            "last_used_at" => $token->last_used_at,
+            "owner" => User::find($token->tokenable_id)->name,
+        ]);
+
+        return response()->json($tokens);
+    }
+
+    public function create_key(Request $request)
+    {
+        $request->validate([
+            'name' => 'required|string|min:3|max:64',
+        ]);
+
+        $token = $request->user()->createToken($request->name)->plainTextToken;
+
+        return response()->json([
+            "key" => $token,
+        ]);
+    }
+
+    public function destroy_key(Request $request, int $id)
+    {
+        $request->user()->tokens()->where('id', $id)->delete();
+        return response()->noContent();
+    }
+
+    public function update_internship_status(int $id)
+    {
+        // TODO: Implement in SCRUM-65
+    }
+}