feat: Ability to access user tokens via Platform API (#11537)

- Add Platform API for generating user tokens 
- Add the swagger documentation.

---------

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

app/views/platform/api/v1/users/token.json.jbuilder

@@ -0,0 +1,9 @@
+json.access_token @resource.access_token.token
+json.expiry nil
+json.user do
+  json.id @resource.id
+  json.name @resource.name
+  json.display_name @resource.display_name
+  json.email @resource.email
+  json.pubsub_token @resource.pubsub_token
+end