This issue should probably be its own Epic.

colorbox handles modals with its content loaded from templates. In order to remove it, every modal has to be implemented with Patternfly React (although not the whole page necessarily).

See for instance https://github.com/3scale/porta/blob/cd7a49109d136a488bb6f2749a1c0352820ea868/app/assets/javascripts/application.js#L168-L169