Add prj_qemu.conf files for dtls_server and dtls_client. Now
it can be tested between two qemus running 802.15.4 dummy driver.
Change-Id: Id94492f90539025854063662c2f0750a0b9ca845
Signed-off-by: Ravi kumar Veeramally <ravikumar.veeramally@linux.intel.com>