Normalize whitespace in source files

Ensure that no source files have trailing whitespace at end of lines and ensure that all files end with a single trailing newline.

This also adds Github Actions to enforce whitespace conventions.

src-ui/src/app/data/websocket-consumer-status-message.ts

@@ -8,4 +8,4 @@ export interface WebsocketConsumerStatusMessage {
   message?: string
   document_id: number
 
-}
+}