Update to 2.3.1 (fix RHBZ#1990668, fix RHBZ#1952348)
    
    - Drop patches, which were all upstreamed
    - Switch BR’s to cmake(…) where appropriate
    - Add -static BR’s for header-only library dependencies
    - Add unarched -static virtual Provides since arched BR’s must not be used
    - Use ninja cmake backend (which was already BR’d)
    - Enable OpenCV (except on armv7hl, for now)
    - Fix ExcludeArch