Bluetooth: tester: Send IUT ready event on tester_init

When tester application has been initialized, send this event
to indicate that Upper Tester can send first BTP command.

Change-Id: Id3f4dd246c4e67982057f9518b4b0036e79a6a01
Signed-off-by: Mariusz Skamra <mariusz.skamra@gmail.com>