Instruction for Client Installation needs to be more prominent

[Simon Greenwood]

The bottom of https://docs.openstack.org/install-guide/environment-packages-ubuntu.html is ambiguous and doesn't highlight the necessity of installing the openstack client. The section 'Sample Installation' is also unclear as to whether it is a requirement at this point.

I would suggest adding something like 'For example, to install Nova on a compute machine:'

and 'The openstack client is the CLI for openstack operations and is installed as follows:'

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-----------------------------------
Release: on 2022-09-14 06:14:18
SHA: 2eb5ba0c8dcc2d015bf407955a8ce40b11d9c1f7
Source: https://opendev.org/openstack/openstack-manuals/src/doc/install-guide/source/environment-packages-ubuntu.rst
URL: https://docs.openstack.org/install-guide/environment-packages-ubuntu.html