Remove usage of sudo

Remove usage of sudo and update prompts.

Fix instructions for creation of stack user:
* These substeps need to be run as root like its said in the intro.
* First change permissions, then run su. Otherwise the user has no
  permissions to change it.

Change-Id: I59c6acb4d50e7866e60366a8d2f01f4fecedf902
Merge "Remove usage of sudo"