CHG: updated helptext for lf t55xx bruteforce

ADD: a ROL function in util.c
ADD: two pwdgen functions in cmdhfmfu.c,  call them with a 7byte UID and get a 4byte number back. Will see if it can be connected with the "hf mfu info" command,  make data extraction easier later on.
ADD: added some more easy pwd in the dictionary file default_pwd.dic