Add GHA workflow to push operator images for PRs

[pmacik]

Motivation

Currently, the acceptance tests with OpenShift (on OpenShift CI) runs only in "local" mode which means it starts a local process of SBO instead of installing the operator into the OpenShift cluster. To make the environment closer to production one, our acceptance tests should run against clusters where the operator is installed using a catalog source or applying an installation yaml file.

ISSUE: https://issues.redhat.com/browse/APPSVC-794

Changes

This PR refactors GitHub worflows so that it build operator, bundle and index images from the PR (a.k.a. "PR images"), pushes it safely to quay.io/redhat-developer/servicebinding-operator repository with the following naming format:

• pr-<PR_NUMBER>-<8_CHAR_COMMIT_ID> = operator image
• pr-<PR_NUMBER>-<8_CHAR_COMMIT_ID>-bundle = bundle image
• pr-<PR_NUMBER>-<8_CHAR_COMMIT_ID>-image = index image

The GH actions for acceptance tests with Kubernetes waits for the above images to be pushed and then use them to run the acceptance test with.

The OpenShift CI jobs for running the acceptance tests are updated to use those images.

All the jobs are correlated through the name of the images based on PR number and the commit ID.

This PR also adds additional workflow that is triggerd when the PR is closed to delete the PR images related to the PR that generated them to make sure the remote repository is not flooded with past PR images.

Testing

I've tested the workflows in the fork repository via couple of PRs such as https://github.com/pmacik/service-binding-operator/pull/115/checks

[openshift-ci]

Skipping CI for Draft Pull Request.
If you want CI signal for your change, please convert it to an actual PR.
You can still manually trigger a test run with /test all

[openshift-ci]

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[pedjak]

look really good, a few remarks, feel free to decide on your own what would you like to take or not

[codecov]

Codecov Report

Merging #972 (4efe1c9) into master (126e3e2) will not change coverage.
The diff coverage is n/a.

❗ Current head 4efe1c9 differs from pull request most recent head 660dee2. Consider uploading reports for the commit 660dee2 to get more accurate results

@@           Coverage Diff           @@
##           master     #972   +/-   ##
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  Coverage   54.27%   54.27%           
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  Files          23       23           
  Lines        1227     1227           
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  Hits          666      666           
  Misses        473      473           
  Partials       88       88           

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