Arnitech controller: the TOD set at boot, and a jump table at $FF00

A new option, ARNITECH_CONTROLLER, on in the mc64 configuration only.
IOINIT starts timer A with CIA #1's TOD on 50 Hz, the mc64's mains, and
if the Arnitech controller's signature "ARNI" is at $DE80, latches its
clock and copies its real time into the TOD, hours first and tenths
last, flipping bit 7 of an hour of 12 first, since the CIA flips it
back when 12 is written. Without the signature the TOD is left alone.

The Arnitech jump table at $FF00: "ARNI", version $01, two entries, and
JMPs from $FF06: $FF06 finds the first Card slot holding a Card of the
type in A (carry clear, the slot in A, its Card window's low byte in
X; carry set if none or no controller), $FF09 sets the TOD as IOINIT
does. $FF48-$FF80 stay clear. The code is in new files under
src/kernal/arnitech; other configurations build as before.

Makefile

@@ -45,6 +45,7 @@ SRCDIR_KERNAL  = $(SRCDIR_COMMON) \
                  src/kernal \
                  src/kernal/,stubs \
                  src/kernal/assets \
+                 src/kernal/arnitech \
                  src/kernal/board_crt \
                  src/kernal/board_m65 \
                  src/kernal/board_u64 \