ccpp: add automatical check for static executables
    
    I am not a C/C++ developer, so please correct me if the check isn't
    valid. But this is basically what I do during review - I find all
    executable files, run `file` on them and see if there is "dynamically
    linked" string present. I usually call also `ldd` on such executables
    but I omitted this to avoid too many bash calls.
    
    In order to implement this check, I needed to access the
    `rpms-unpacked` directory. This isn't done by any other plugin yet,
    and so far only (bash) scripts are doing such checks. I am
    intentionally trying to set a precedent here because I have some more
    checks on my mind and I would like to touch bash as little as
    possible. Ideally not at all.