Filter by issue type `Requirement`

• For requirements management, we want a UI to be able to see a list of long-lasting requirements for an application/product.
• This helps users understand what these requirements are as a reference, serving as business-logic documentation.
• The idea here is to leverage a new issue type called Requirement (i.e. https://gitlab.com/gitlab-org/gitlab-ee/issues/8767), and then be able to filter this in the issues list. This would allow users to always see a list of requirements.