* Add additional network configuration options to external Openstack CCM (#6083)

* Change the default version of external openstack cloud controller image to v1.18.1 since there was an issue in v1.18.0 where some IPs of the private network were ignored

* Change Network section in external-openstack-cloud-config.j2 to Networking

* Add networking customization information in the openstack documentation

This updates MetalLB README as following
- Remove unnecessary markdown to read it easily on github
- Make words consistency (kubernetes, loadbalancer)
- Add change-required option

Change-Id: I83a7101a6cd99eb531d8385de5c31aee4f474469

Due to lack of requirements installation on Azure README, the error
can happen:

 "The ipaddr filter requires python's netaddr be installed on the
  ansible controller"

It is nice to add the installation for Azure users.

* Create namespace when dashboard deployment uses customized namespace.

* Fix syntax.

The 98e7a07f commit udpates the
dashboard version to 2.0.0 but it enable skip login flag wasn't
updated. This change updates its identation to avoid issues when
dashboard_skip_login is enabled.

As of pypy 7.3.0, we can utilize the official pypy project as opposed to
the previously used "portable-pypy" distribution.

apply-rg.sh was for Azure command version 1("azure" command) and the
command is old and version 2("az" command) is officially used today.
apply-rg_2.sh was for the version 2. In addition, the README[1] says
we need to run apply-rg.sh for applying templates.

This renames apply-rg_2.sh to apply-rg.sh for common usages of the
version 2.

[1]: https://github.com/kubernetes-sigs/kubespray/tree/master/contrib/azurerm#generating-and-applying