Milestone M35 - category display fix, bulk url deletion issue, attachment duplication and more

Let's go through what we got done in Milestone M35 (Apr 21 - May 04).

Bug fixes ⚒️

• Addressed Brakeman warnings by resolving potential SQL injection and remote code execution issues in the code.

• Fixed slow transactions and database operations monitored in NewRelic.

• Improved the category display logic on the end-user side to ensure that a category is only visible if it contains at least one article.

• Resolved the error in bulk URL deletion on the report page.

• Fixed "something went wrong" error when publishing an article with only title and no content.

• Resolved an issue where renaming attachments in articles resulted in duplicate attachments.