Add 07_multithread_rr and 08_thread_control_apis

apps/07_multithread_rr/prj.conf

@@ -0,0 +1,12 @@
+CONFIG_SERIAL=y
+CONFIG_CONSOLE=y
+CONFIG_PRINTK=y
+
+# Enable zephyr timeslicing
+CONFIG_TIMESLICING=y
+
+# Set the timeslice lenght in milliseconds
+CONFIG_TIMESLICE_SIZE=10
+
+# Timeslicing only applies to threads whose priority is numerically >= this value(e.g. 0)
+CONFIG_TIMESLICE_PRIORITY=0