chore: Ability to Disable Gravatars (#5027)

fixes: #3853

- Introduced DISABLE_GRAVATAR Global Config, which will stop chatwoot from making API requests to gravatar
- Cleaned up avatar-related logic and centralized it into the avatarable concern
- Added specs for the missing cases
- Added migration for existing installations to move the avatar to attachment, rather than making the API that results in 404.

app/jobs/avatar/avatar_from_gravatar_job.rb

@@ -0,0 +1,13 @@
+class Avatar::AvatarFromGravatarJob < ApplicationJob
+  queue_as :low
+
+  def perform(avatarable, email)
+    return if GlobalConfigService.load('DISABLE_GRAVATAR', '').present?
+    return if email.blank?
+    return if avatarable.avatar_url.present?
+
+    hash = Digest::MD5.hexdigest(email)
+    gravatar_url = "https://www.gravatar.com/avatar/#{hash}?d=404"
+    Avatar::AvatarFromUrlJob.perform_later(avatarable, gravatar_url)
+  end
+end

app/jobs/avatar/avatar_from_url_job.rb

@@ -0,0 +1,15 @@
+class Avatar::AvatarFromUrlJob < ApplicationJob
+  queue_as :default
+
+  def perform(avatarable, avatar_url)
+    return unless avatarable.respond_to?(:avatar)
+
+    avatar_file = Down.download(
+      avatar_url,
+      max_size: 15 * 1024 * 1024
+    )
+    avatarable.avatar.attach(io: avatar_file, filename: avatar_file.original_filename, content_type: avatar_file.content_type)
+  rescue Down::NotFound, Down::Error => e
+    Rails.logger.error "Exception: invalid avatar url #{avatar_url} : #{e.message}"
+  end
+end

app/jobs/contact_avatar_job.rb

@@ -1,15 +0,0 @@
-class ContactAvatarJob < ApplicationJob
-  queue_as :default
-
-  def perform(contact, avatar_url)
-    avatar_file = Down.download(
-      avatar_url,
-      max_size: 15 * 1024 * 1024
-    )
-    contact.avatar.attach(io: avatar_file, filename: avatar_file.original_filename, content_type: avatar_file.content_type)
-  rescue Down::NotFound
-    contact.avatar.attachment.destroy! if contact.avatar.attached?
-  rescue Down::Error => e
-    Rails.logger.error "Exception: invalid avatar url #{avatar_url} : #{e.message}"
-  end
-end