Feature: Knowledge Base APIs (#1002)

- Introduce models & migrations for portals, categories, folders and articles
- CRUD API for portals
- CRUD API for categories

Addresses: #714

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

app/controllers/api/v1/accounts/kbase/base_controller.rb

@@ -0,0 +1,9 @@
+class Api::V1::Accounts::Kbase::BaseController < Api::V1::Accounts::BaseController
+  before_action :portal
+
+  private
+
+  def portal
+    @portal ||= Current.account.kbase_portals.find_by(id: params[:portal_id])
+  end
+end