feat: SLA CRUD APIs (EE) (#7027)

Fixes: https://linear.app/chatwoot/issue/CW-1613/sla-api

Co-authored-by: Sojan Jose <sojan@pepalo.com>

config/routes.rb

@@ -64,6 +64,7 @@ Rails.application.routes.draw do
             post :execute, on: :member
             post :attach_file, on: :collection
           end
+          resources :sla_policies, only: [:index, :create, :show, :update, :destroy]
           resources :campaigns, only: [:index, :create, :show, :update, :destroy]
           resources :dashboard_apps, only: [:index, :show, :create, :update, :destroy]
           namespace :channels do