Add way to return ShellCommand parameters as list

This is useful if command is going to be run in the POD as arguments
for the POD's command should be passed to the OpenShift client as list
of attributes rather then string.

Related: #TOBIKO-131
Change-Id: I9da5bfb8b0f98ed86c4dff54039392537b8286bf

tobiko/shell/sh/_command.py

@@ -37,6 +37,9 @@ class ShellCommand(tuple):
     def __contains__(self, item) -> bool:
         return item in str(self)
 
+    def as_list(self):
+        return str(self).split(" ")
+
 
 def shell_command(command: ShellCommandType,
                   **shlex_params) -> ShellCommand: