Add salesforce connector

Author: swati354

backend/danswer/configs/constants.py

@@ -100,6 +100,7 @@ class DocumentSource(str, Enum):
     CLICKUP = "clickup"
     MEDIAWIKI = "mediawiki"
     WIKIPEDIA = "wikipedia"
+    SFKBARTICLES = "sfkbarticles"
     S3 = "s3"
     R2 = "r2"
     GOOGLE_CLOUD_STORAGE = "google_cloud_storage"