Add isort to the pre-commit configuration and apply it to the whole project (#595)

* Apply isort to the entire repository
* Fix missing import issues in text_to_entries
* Fix imports in migration files

tests/test_gpt4all_chat_director.py

@@ -1,13 +1,10 @@
-# Standard Packages
 import urllib.parse
 from urllib.parse import quote
 
-# External Packages
 import pytest
-from freezegun import freeze_time
 from faker import Faker
+from freezegun import freeze_time
 
-# Internal Packages
 from khoj.processor.conversation import prompts
 from khoj.processor.conversation.utils import message_to_log
 from tests.helpers import ConversationFactory