Feat: GitHub connector (#12314)

### What problem does this PR solve?

Feat: GitHub connector

### Type of change

- [x] New Feature (non-breaking change which adds functionality)

common/data_source/config.py

@@ -58,6 +58,7 @@ class DocumentSource(str, Enum):
     GITHUB = "github"
     GITLAB = "gitlab"
 
+    
 class FileOrigin(str, Enum):
     """File origins"""
     CONNECTOR = "connector"
@@ -234,6 +235,8 @@ _REPLACEMENT_EXPANSIONS = "body.view.value"
 
 BOX_WEB_OAUTH_REDIRECT_URI = os.environ.get("BOX_WEB_OAUTH_REDIRECT_URI", "http://localhost:9380/v1/connector/box/oauth/web/callback")
 
+GITHUB_CONNECTOR_BASE_URL = os.environ.get("GITHUB_CONNECTOR_BASE_URL") or None
+
 class HtmlBasedConnectorTransformLinksStrategy(str, Enum):
     # remove links entirely
     STRIP = "strip"