scripts: add "FILE" and "CFG" debug levels.
I ran into some minor difficulties looking through the build log for a
particular file: I wasn't interested in seeing it unpacked, but only
when it is built or installed. Adding these two levels allows me to
differentiate between those cases.
[Yann E. MORIN: Those are blind log levels, and are used only to search
in the build-log afterward.]
Signed-off-by: Anthony Foiani <anthony.foiani@gmail.com>