Chore: Web widget Inbox Tech Debts (#738)

* Chore: Webwidget Inbox Tech Debts

* Additional customization options creating Web Widget
* Changes to edit Page for Web Widget
* Remove the WebWidget API end points
* Minor chores

Address: #680, #502

Co-authored-by: Pranav Raj Sreepuram <pranavrajs@gmail.com>

db/migrate/20200417093432_remove_name_from_channels.rb

@@ -0,0 +1,35 @@
+class RemoveNameFromChannels < ActiveRecord::Migration[6.0]
+  def change
+    remove_column :channel_facebook_pages, :name, :string
+    remove_column :channel_twitter_profiles, :name, :string
+    migrate_web_widget_name_to_inbox
+    remove_column :channel_web_widgets, :website_name, :string # rubocop:disable Rails/BulkChangeTable
+
+    add_column :channel_web_widgets, :welcome_title, :string
+    add_column :channel_web_widgets, :welcome_tagline, :string
+    add_column :channel_web_widgets, :agent_away_message, :string
+    purge_orphan_facebook_pages
+    remove_avatars_from_channel_to_inbox
+  end
+
+  def purge_orphan_facebook_pages
+    Channel::FacebookPage.all.each do |facebook_page|
+      facebook_page.destroy! if facebook_page.inbox.nil?
+    end
+  end
+
+  def migrate_web_widget_name_to_inbox
+    Channel::WebWidget.all.each do |widget|
+      widget.inbox.name = widget.website_name
+      widget.save!
+    end
+  end
+
+  def remove_avatars_from_channel_to_inbox
+    Channel::FacebookPage.all.each do |facebook_page|
+      next unless facebook_page.avatar
+
+      facebook_page.avatar.purge
+    end
+  end
+end