Detect and use oc / kubectl for integration tests

[feloy]

Please specify the area for this PR

What does does this PR do / why we need it:

Which issue(s) this PR fixes:

Fixes devfile/api#1239

PR acceptance criteria:

• Test Coverage
  • Are your changes sufficiently tested, and are any applicable test cases added or updated to cover your changes?
• Gosec scans
  • Fix all MEDIUM and higher findings and/or annotate a finding per gosec instructions: https://github.com/securego/gosec#annotating-code to address why a finding is not a security issue

Documentation

• Does the registry operator documentation need to be updated with your changes?

How to test changes / Special notes to the reviewer:

• Run make test-integration with oc only, kubectl only, none of them present in the PATH.
• Define K8S_CLI with the preferred cli to use

[rm3l]

Also, could you update this line in the README.md file accordingly?
https://github.com/feloy/registry-operator/blob/feature-1239/test-with-kubectl/README.md?plain=1#L99

[codecov]

Codecov Report

All modified lines are covered by tests ✅

Comparison is base (b06b836) 25.86% compared to head (1f1015b) 25.86%.
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main      #53   +/-   ##
=======================================
  Coverage   25.86%   25.86%           
=======================================
  Files          25       25           
  Lines        1415     1415           
=======================================
  Hits          366      366           
  Misses       1026     1026           
  Partials       23       23           

see 4 files with indirect coverage changes

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[rm3l]

LGTM. Could you just update this line in the README.md file accordingly (especially to mention the use of the env var)?
https://github.com/feloy/registry-operator/blob/feature-1239/test-with-kubectl/README.md?plain=1#L99

[rm3l]

LGTM. Fixing the DCO checks and it should be good.

[openshift-ci]

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This pull-request has been approved by: feloy, rm3l

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