Allow user lookup by apikey

This plugin breaks the GCode Viewer as is. When using this plugin and accessing the GCode Viewer, one gets this error in the log:

TypeError: findUser() got an unexpected keyword argument 'apikey'

This commit ensures that the findUser function knows how to handle the 'apikey' parameter from ~/octoprint/server/util/__init__.py if submitted.

octoprint_auth_ldap/__init__.py

@@ -50,8 +50,8 @@ class LDAPUserManager(FilebasedUserManager,
         if FilebasedUserManager.findUser(self, username) is not None:
             return FilebasedUserManager.changeUserPassword(self, username, password)
 
-    def findUser(self, userid=None, session=None):
-        local_user = FilebasedUserManager.findUser(self, userid, session)
+    def findUser(self, userid=None, apikey=None, session=None):
+        local_user = FilebasedUserManager.findUser(self, userid, apikey, session)
         #If user not exists in local database, search it on LDAP
         if userid and not local_user:
             if(self.findLDAPUser(userid)):