sanitycheck: Add Renode cmake configuration

By default Renode is searched for in the system PATH.
The PID is stored in renode.pid - the application must be killed with a
signal after a test.

With the XWT gui layer disabled all UART output is directed to the
stdout.

Signed-off-by: Dawid Wojciechowski <dwojciechowski@internships.antmicro.com>
Signed-off-by: Jan Kowalewski <jkowalewski@antmicro.com>
Signed-off-by: Piotr Zierhoffer <pzierhoffer@antmicro.com>