replay API is used deeply within TCG common code (common to user
and system emulation). Unfortunately "sysemu/replay.h" requires
some QAPI headers for few system-specific declarations, example:

  void replay_input_event(QemuConsole *src, InputEvent *evt);

Since commit c2651c0e ("qapi/meson: Restrict UI module to system
emulation and tools") the QAPI header defining the InputEvent is
not generated anymore.
To keep it simple, extract the 'core' replay prototypes to a new
"exec/replay-core.h" header which we include in the TCG code that
doesn't need the rest of the replay API.

Reviewed-by: Pavel Dovgalyuk <Pavel.Dovgalyuk@ispras.ru>
Message-Id: <20221219170806.60580-5-philmd@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>