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>

app/services/imap/google_fetch_email_service.rb

@@ -0,0 +1,17 @@
+class Imap::GoogleFetchEmailService < Imap::BaseFetchEmailService
+  def fetch_emails
+    return if channel.provider_config['access_token'].blank?
+
+    fetch_mail_for_channel
+  end
+
+  private
+
+  def authentication_type
+    'XOAUTH2'
+  end
+
+  def imap_password
+    Google::RefreshOauthTokenService.new(channel: channel).access_token
+  end
+end