cloudmonkey: add -p option to allow overriding profile

- -p or --profile overrides current selected profile for cloudmonkey
- this won't write the new profile/selection to config thereby allowing many
  cloudmonkey instances run both in interpretor and bash modes with different
  profile sharing common ui and core config options

Signed-off-by: Rohit Yadav <rohit.yadav@shapeblue.com>