Feat: Support for Microsoft Oauth in Email Channel (#6227)

- Adds the backend APIs required for Microsoft Email Channels

Co-authored-by: Pranav Raj S <pranav@chatwoot.com>
Co-authored-by: Sojan <sojan@pepalo.com>

Gemfile

@@ -37,6 +37,8 @@ gem 'json_schemer'
 gem 'rack-attack'
 # a utility tool for streaming, flexible and safe downloading of remote files
 gem 'down', '~> 5.0'
+# authentication type to fetch and send mail over oauth2.0
+gem 'gmail_xoauth'
 
 ##-- for active storage --##
 gem 'aws-sdk-s3', require: false
@@ -186,3 +188,5 @@ group :development, :test do
   gem 'spring'
   gem 'spring-watcher-listen'
 end
+# worked with microsoft refresh token
+gem 'omniauth-oauth2'