Backport of CNI: Add support for OpenShift and Multus into release/0.49.x

[hc-github-team-consul-ecosystem]

Backport

This PR is auto-generated from #1527 to be assessed for backporting due to the inclusion of the label backport/0.49.x.

The below text is copied from the body of the original PR.

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Changes proposed in this PR:

This PR adds support for OpenShift and Multus in CNI. OpenShift uses Multus as the base CNI plugin.

• Added SecurityContextConstraints CRD so that CNI has the permissions to run on OpenShift and gave the consul-cni service account permissions to reach OpenShifts SCC CRD.
• Added a --multus flag to the CNI installer so that the flag can be used by the CNI plugin.
• When --multus flag is set, create a default Network Attachment Definition CRD for Multus to use. Note, Pods require an annotation in order for Multus to run the consul-cni plugin. Please see Multus documentation for more information about how to use Multus.
• Fix: Fixed installer to rename .conf file .conflist file when consul-cni is added to a base plugin.
• Improvement: The plugin is now more consistent at updating annotations.

How I've tested this PR:

• Manual testing of Multus on OpenShift
• Manual testing of Multus on Kind
• Acceptance and unit tests.

How I expect reviewers to test this PR:

👀

Checklist:

• Tests added
• CHANGELOG entry added

  HashiCorp engineers only, community PRs should not add a changelog entry.
  Entries should use present tense (e.g. Add support for...)

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Overview of commits

• 8a97da4 - 69fe217 - d46addf