[vcloud_director] ensure that MetadataEntry is a list
[vcloud_director] Show guest customization "admin password auto"

Guest customization setting "admin password auto" was retrieved but not
shown.
[vcloud_director] Handle Guest admin password

Admin passwords can be retrieved and modified using the VMWare console,
so it's useful to allow the same operations here.

Moreover, when an admin password is enabled and "admin password auto" is
false, it's impossible to modify Guest settings.
i.e., "The administrator password cannot be empty when it is enabled and
automatic password generation is not selected."

This patch also fixes `put_guest_customization_section_vapp` where an
AdminPassword element was never created.
[xenserver] Adding more XenServer Models
Adding more XenServer models
Forget to reference models on main class
Merge pull request #2475 from zertico/adding_more_models

[xenserver] Adding more XenServer Models
expanding/rewriting the getting-help/involved section of README
fix spacing for getting help section of README
Merge pull request #2459 from alphagov/ensure_metadata_entry_is_list

[vcloud_director] ensure that MetadataEntry is a list
vApp rename via put_vapp_name_and_description
Merge pull request #2464 from astratto/guest_password

[vcloud_director] Fix Guest admin password settings
use std options={} format for optional parameters
[vclouddirector] correct put_vapp_name_and_description documentation
Merge pull request #2481 from alphagov/vcloud_director_put_vapp

vApp rename via put_vapp_name_and_description