Eliminate Company\CompaniesController, introduce owner role

Redistribute methods:
- show() -> BootstrapController::currentCompany()
- store(), destroy(), userCompanies() -> Admin\CompaniesController
- transferOwnership() -> CompanySettingsController

Security fix: introduce 'owner' role for company-level admin, distinct
from 'super admin' which is now global platform admin only.
- CompanyService::setupRoles() creates 'owner' role per company
- Company creation assigns scoped 'owner' role instead of global 'super admin'
- Seeders updated to assign 'owner'

Migration renames all existing company-scoped 'super admin' roles to
'owner' and ensures every company owner has the role assigned.

database/seeders/UsersTableSeeder.php

@@ -37,7 +37,7 @@ class UsersTableSeeder extends Seeder
         $user->companies()->attach($company->id);
         BouncerFacade::scope()->to($company->id);
 
-        $user->assign('super admin');
+        $user->assign('owner');
 
         Setting::setSetting('profile_complete', 0);
         // Set version.