Add "Rationale" Filter with Options "Available/Not Available"

[Kale98]

As a user, I want to filter items by the category "Rationale" with options "Available" and "Not Available," so I can easily find content based on whether a rationale is provided.

UI Placement:

The filter should be placed in the existing filter section for easy access and usability.

ACCEPTANCE CRITERIA:

• A new filter titled "Rationale" should be added to the filtering options.
• The "Rationale" filter should have two options:
  a) Available
  b) Not Available
• The filter should apply instantly, narrowing the results based on the selection (Available or Not Available).
• The filter should work on the Latest Updates page: Filter applies to whether rationale is available.