MGMT-16745: Add platform field to R&C and installation pages

[jgyselov]

https://issues.redhat.com/browse/MGMT-16745

[openshift-ci-robot]

@jgyselov: This pull request references MGMT-16745 which is a valid jira issue.

Warning: The referenced jira issue has an invalid target version for the target branch this PR targets: expected the bug to target the "4.17.0" version, but no target version was set.

In response to this:

https://issues.redhat.com/browse/MGMT-16745

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[openshift-ci]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: jgyselov

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[ammont82]

@jgyselov about the PlatformIntegrationNote:

• In case of Nutanix and vSphere - it's necessary
• In case of OCI - it's not necessary