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/interceptors/csrf.interceptor.ts

@@ -20,7 +20,7 @@ export class CsrfInterceptor implements HttpInterceptor {
     let prefix = ""
     if (this.meta.getTag('name=cookie_prefix')) {
       prefix = this.meta.getTag('name=cookie_prefix').content
-    }    
+    }
     let csrfToken = this.cookieService.get(`${prefix?prefix:''}csrftoken`)
     if (csrfToken) {
      request = request.clone({