modal-xxl size

[coliff]

Prerequisites

• I have searched for duplicate or closed feature requests
• I have read the contributing guidelines

Proposal

Bootstrap has support for modal sizes for all responsive breakpoints except XXL. There is a full-screen option for Modals but it'd make sense to me to have a XXL modal option. I would like to use it if it was added :-)

Motivation and context

Full-screen modals are useful for many contexts, but they can break immersion from the main site and XXL modals would be useful for some use cases.