feat: add Google Email fetch and OAuth token refresh service (#9603)

This PR adds the following changes

1. Add `Imap::GoogleFetchEmailService` and
`Google::RefreshOauthTokenService`. The
`Google::RefreshOauthTokenService` uses
`OmniAuth::Strategies::GoogleOauth2` which is already added as a packge
2. Update `Inboxes::FetchImapEmailsJob` to handle Google inboxes
3. Add SMTP settings for Google in `ConversationReplyMailerHelper` to
allow sending emails


## Preview

#### Incoming emails

![CleanShot 2024-06-06 at 17 17
22@2x](https://github.com/chatwoot/chatwoot/assets/18097732/9d7d70d1-68e3-4c16-b1ca-e5a2e6f890e8)

#### Outgoing email

![CleanShot 2024-06-06 at 17 18
05@2x](https://github.com/chatwoot/chatwoot/assets/18097732/1b4abf0e-e311-493e-bdc8-386886afbb25)

---------

Co-authored-by: Muhsin Keloth <muhsinkeramam@gmail.com>

spec/models/channel/email_spec.rb

@@ -35,4 +35,15 @@ RSpec.describe Channel::Email do
       expect(channel.microsoft?).to be(true)
     end
   end
+
+  context 'when google?' do
+    it 'returns false' do
+      expect(channel.google?).to be(false)
+    end
+
+    it 'returns true' do
+      channel.provider = 'google'
+      expect(channel.google?).to be(true)
+    end
+  end
 end