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>

app/controllers/concerns/microsoft_concern.rb

@@ -0,0 +1,22 @@
+module MicrosoftConcern
+  extend ActiveSupport::Concern
+
+  def microsoft_client
+    ::OAuth2::Client.new(ENV.fetch('AZURE_APP_ID', nil), ENV.fetch('AZURE_APP_SECRET', nil),
+                         {
+                           site: 'https://login.microsoftonline.com',
+                           authorize_url: 'https://login.microsoftonline.com/common/oauth2/v2.0/authorize',
+                           token_url: 'https://login.microsoftonline.com/common/oauth2/v2.0/token'
+                         })
+  end
+
+  private
+
+  def parsed_body
+    @parsed_body ||= Rack::Utils.parse_nested_query(@response.raw_response.body)
+  end
+
+  def base_url
+    ENV.fetch('FRONTEND_URL', 'http://localhost:3000')
+  end
+end