Replace serde_yaml with yaml_serde

[adwk67]

Description

Part of stackabletech/issues#898.

Definition of Done Checklist

• Not all of these items are applicable to all PRs, the author should update this template to only leave the boxes in that are relevant
• Please make sure all these things are done and tick the boxes

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
• Code contains useful logging statements
• (Integration-)Test cases added
• Documentation added or updated. Follows the style guide.
• Changelog updated
• Cargo.toml only contains references to git tags (not specific commits or branches)

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

[adwk67]

Pending tests.....

[adwk67]

Tests:

--- PASS: kuttl (371.28s)
    --- PASS: kuttl/harness (0.00s)
        --- PASS: kuttl/harness/smoke_druid-37.0.0_zookeeper-3.9.6_hadoop-3.5.0_openshift-false (371.27s)
PASS

--- PASS: kuttl (234.17s)
    --- PASS: kuttl/harness (0.00s)
        --- PASS: kuttl/harness/overrides_druid-latest-37.0.0_zookeeper-latest-3.9.6_hadoop-latest-3.5.0_openshift-false (234.16s)
PASS

[NickLarsenNZ]

LGTM