feat: Google OAuth for login & signup (#6346)

This PR adds Google OAuth for all existing users, allowing users to log in or sign up via their Google account.

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Co-authored-by: Pranav Raj S <pranav@chatwoot.com>
Co-authored-by: Fayaz Ahmed <15716057+fayazara@users.noreply.github.com>
Co-authored-by: Sojan <sojan@pepalo.com>

config/initializers/omniauth.rb

@@ -0,0 +1,5 @@
+Rails.application.config.middleware.use OmniAuth::Builder do
+  provider :google_oauth2, ENV.fetch('GOOGLE_OAUTH_CLIENT_ID', nil), ENV.fetch('GOOGLE_OAUTH_CLIENT_SECRET', nil), {
+    provider_ignores_state: true
+  }
+end