dleyna-core: Add recipe

dleyna-core is a library of utility functions needed by
other dLeyna packages (most notably "dleyna-connector-dbus"
"dleyna-server" and "dleyna-renderer").

It provides APIs for logging, error, settings, task
management and an IPC abstraction API.

Signed-off-by: Manuel Bachmann <manuel.bachmann@iot.bzh>
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>