Implement OAuth2 server, link oauth:Client and auth::Oauth2Client, implement permission checks

app/models/ldap/Client.model.js

@@ -35,15 +35,23 @@ class ClientModel extends Model {
         return client
     }
 
+    async invoke() {
+        this.last_invocation = new Date
+    }
+
     async user() {
         const User = this.models.get('auth:User')
         return User.findById(this.user_id)
     }
 
+    async application() {
+        const Application = this.models.get('Application')
+        return Application.findOne({ active: true, ldap_client_ids: this.id })
+    }
+
     async to_api() {
         const User = this.models.get('auth:User')
         const user = await User.findById(this.user_id)
-
         const role_permissions = user.roles.map(x => this.configs.get('auth.roles')[x])
 
         return {