scripts/sequence-patch.sh: let "--fast", "--rapid" and "" behave consistently
    
    Today scripts/sequence-patch.sh will stop before applying a patch when
    being called with "--fast" or "--rapid" and a patch name, while it will
    apply the named patch when being called without "--fast" or "--rapid".
    
    Change that by letting apply_patches() use the PATCHES_BEFORE[] and
    PATCHES_AFTER[] arrays as apply_rapid_patches() and
    apply_fast_patches() are doing already.
    
    In order to keep the capability to single step through the remaining
    patches add a function for that purpose.