A script to run CI tests locally.

Added ./run_locally.sh script. The script takes one argument being the testcase
that one wants to run. The testcase is run locally. This means that some testcases that
utilize hardware resources will not run. However most if not all rfsimulator testcases
should run as in CI.

To this end, the CI python scripting framework was updated, adding --local flag which changes
the script behavior as follows:
 - overrides <node> and <srv_node> XML elements to 'localhost' so all commands are executed locally
 - Avoid running image pull, image cleanup and workspace creation steps of the scripts:
   user is responsible for that

ci-scripts/cls_cmd.py

@@ -217,6 +217,8 @@ class RemoteCmd(Cmd):
 		return client
 
 	def _lookup_ssh_config(hostname):
+		if is_local(hostname):
+			raise ValueError("Using localhost as SSH target is not allowed: use LocalCmd instead.")
 		ssh_config = paramiko.SSHConfig()
 		user_config_file = os.path.expanduser("~/.ssh/config")
 		if os.path.exists(user_config_file):