Chore: Parse quoted text in incoming emails (#883) (#884)

* Chore: Parse quoted text in incoming emails (#883)
* Parsed the quoted text and replies in incoming emails and store them separately
* Did this parsing for plain text and html part of emails
* In the chat window, we will only show the parsed reply alone

* Conversation mailbox test fixes (#883)

spec/mailboxes/conversation_mailbox_spec.rb

@@ -8,7 +8,7 @@ RSpec.describe ConversationMailbox, type: :mailbox do
     let(:reply_mail) { create_inbound_email_from_fixture('reply.eml') }
     let(:conversation) { create(:conversation, assignee: agent) }
     let(:described_subject) { described_class.receive reply_mail }
-    let(:serialized_attributes) { %w[content number_of_attachments subject date to from in_reply_to cc bcc message_id] }
+    let(:serialized_attributes) { %w[text_content html_content number_of_attachments subject date to from in_reply_to cc bcc message_id] }
 
     before do
       # this UUID is hardcoded in the reply.eml, that's why we are updating this
@@ -19,7 +19,7 @@ RSpec.describe ConversationMailbox, type: :mailbox do
     end
 
     it 'add the mail content as new message on the conversation' do
-      expect(conversation.messages.last.content).to eq("Let's talk about these images:\r\n\r\n")
+      expect(conversation.messages.last.content).to eq("Let's talk about these images:")
     end
 
     it 'add the attachments' do