Improve shell capturing in init containers

[maltesander]

Description

We have some integration test failures in products using HDFS, where the format image somehow fails.

Failed to start namenode.\njava.io.FileNotFoundException: No valid image files found

and

Failed to start namenode.\norg.apache.hadoop.hdfs.qjournal.client.QuorumException: Could not format one or more JournalNodes. 1 exceptions thrown:\n10.42.11.24:8485: End of File Exception between local host is: \"hdfs-namenode-default-0/10.42.11.25\"; destination host is: \"hdfs-journalnode-default-0.hdfs-journalnode-default.kuttl-test-calm-hookworm.svc.cluster.local\":8485; : java.io.EOFException; For more details see:  http://wiki.apache.org/hadoop/EOFException

We previously did not catch the init container shell output properly, which is done in this PR.

Definition of Done Checklist

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Author

• Changes are OpenShift compatible
• CRD changes approved
• CRD documentation for all fields, following the style guide.
• Helm chart can be installed and deployed operator works
• Integration tests passed (for non trivial changes)
• Changes need to be "offline" compatible
• Links to generated (nightly) docs added
• Release note snippet added

Reviewer

• Code contains useful comments
• Changelog updated

Acceptance

• Feature Tracker has been updated
• Proper release label has been added
• Links to generated (nightly) docs added
• Release note snippet added
• Add type/deprecation label & add to the deprecation schedule
• Add type/experimental label & add to the experimental features tracker

[siegfriedweber]

The changes look good to me. However, the HDFS pods often restart and the logging integration test sometimes fails because the cluster does not become ready within 10 minutes.