refactor(webhook): remove Webhook model and related logic; add migrations to drop webhooks and kubernetes tables

app/Models/Kubernetes.php

@@ -1,5 +0,0 @@
-<?php
-
-namespace App\Models;
-
-class Kubernetes extends BaseModel {}

app/Models/Webhook.php

@@ -1,15 +0,0 @@
-<?php
-
-namespace App\Models;
-
-use Illuminate\Database\Eloquent\Model;
-
-class Webhook extends Model
-{
-    protected $guarded = [];
-
-    protected $casts = [
-        'type' => 'string',
-        'payload' => 'encrypted',
-    ];
-}