chore(deps): upgrade operator deps and renovate config to use go 1.21 and ubi 9.4

[Fortune-Ndlovu]

Description

Upgrade the operator to use Go 1.21 and UBI 9.4 to ensure the resulting image is A grade.

Which issue(s) does this PR fix or relate to

• Fixes #RHIDP-2646 - https://issues.redhat.com/browse/RHIDP-2646

PR acceptance criteria

• Tests
• Documentation
• If the bundle manifests have been updated, make sure to review the rhdh-operator.csv.yaml file accordingly

How to test changes / Special notes to the reviewer

1. Verify the build works by running make image-build.
2. Ensure all tests pass by running make test.
3. Review the changes to go.mod, Dockerfile, and renovate config.

[rm3l]

Job failed because of two many files changed: https://github.com/janus-idp/operator/actions/runs/9906103267/job/27367027374?pr=398

We are not vendoring at this time (see https://issues.redhat.com/browse/RHIDP-1236?focusedId=24349328&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-24349328), so please remove the vendor directory.

[rm3l]

/cc @nickboldt

For additional review.

[openshift-ci]

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This pull-request has been approved by: nickboldt

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