Add new parameter which renames the builtin administrator user instead of
creating a new one. The new account name is provided by the metadata
service or specified in the conf file using the "username" option.
- rename_admin_user: type bool, default value False
Change-Id: I5f8c98c4854db21f7bb8eeddb81e9cf98c309a01
Implements: blueprint add-rename-administrator-option
Co-Authored-By: Paula Madalina Crismaru <pcrismaru@cloudbasesolutions.com>