Patch servos code for move

- Have `Servo::attach` explicitly return -1 if it fails
- Check for -1 in `Servo::move` because `servoIndex` might be 0
- Make `attach` / `detach` calls conditional on `SERVO_LEVELING`
- Move `SERVO_LEVELING` define to `Conditionals.h`

Elsewhere DRYRUN turns off the heating elements
and ignores constraints on them.

Here, whenever motion is entered into the planner,
if DRY RUN is set, we instantly act as if the E_AXIS
is in the desired final position.

to make clear - it's not a question but an order.

as sugested by @c-born
inhttps://github.com/MarlinFirmware/Marlin/issues/1885#issuecomment-92618240

and cleaned out some tabs.

Everything else is a rebased PR#2017 as proposed by @CptanPanic

by replacing the sequences (attach, write, delay, detach), and their conditions with the new function in Marlin.main.cpp
and removing the old configuration in the ABL part of Configuration.h

DEACTIVATE_SERVOS_AFTER_MOVE is ought to replace PROBE_SERVO_DEACTIVATION_DELAY.
But it will work on all servo moves, not only the probe servo moves.

move(pin, angel) - Sequence of attach(pin), write(angel),
                   if DEACTIVATE_SERVOS_AFTER_MOVE is defined waits SERVO_DEACTIVATION_DELAY, than detaches.

As we have jitter on the servos during moves of the steppers, and detaching them improves this behaviour,
the usual sequence to handle a servo movement is:
attach(pin)
write(angel)
delay(until the servo finished the move)
detache()

Here a function to handle the complete sequence.

Slightly updated translation.