[CPDEV-102250] Remove Cloud Provider Plugin support

[n549]

Description

The requestor of openstack cloud provider support doesn't use it any more, the current description of its possible usage is obsolete and needs to be removed.

Fixes # (issue)
CPDEV-102250

Relates to the issue #666

Solution

1. Installation.md is updated.
2. Hardcoded update of kubelet's arguments for openstack cloud provider is removed.

How to apply

Test Cases

Checklist

• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• Integration CI passed
• Unit tests. If Yes list of new/changed tests with brief description
• There is no merge conflicts

Unit tests

Indicate new or changed unit tests and what they do, if any.