The TTY handling in Finit has always been a bit of a patch work. This
commit is an attempt at a first cleanup and simplification.
Included is a brand new built-in getty which should work fine on both
virtual and serial consoles. It is however completely untested on the
latter serial consoles.
Still TODO: add support for /etc/securetty, add support for actually
setting TERM when calling /bin/login.
Signed-off-by: Joachim Nilsson <troglobit@gmail.com>