Add execute_live function

The function will execute a command and print the output to the console
while the command is still running

src/main/python/ddadevops/python_util.py

@@ -1,4 +1,4 @@
-from subprocess import check_output
+from subprocess import check_output, Popen, PIPE
 import sys
 
 def execute(cmd, shell=False):
@@ -8,5 +8,12 @@ def execute(cmd, shell=False):
         output = check_output(cmd, shell=shell)
     return output.rstrip()
 
+def execute_live(cmd):
+    p = Popen(cmd, stdout=PIPE)
+    for line in iter(p.stdout.readline, b''):
+        print(line.decode('utf-8'), end='')
+    p.stdout.close()
+    p.wait()
+
 def filter_none(list):
     return [x for x in list if x is not None]