feat: Add health-checks for Elasticsearch #6052

[pupseba]

Add health-checks for Elasticsearch operated resources.

It considers both "phase" and "health" as provided by the Elasticsearch object itself.
https://github.com/elastic/cloud-on-k8s/blob/6bb3dc7f6c0d8753a30f87ce69b7de8f0d9e0f35/pkg/apis/elasticsearch/v1/elasticsearch_types.go#L347

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[codecov]

Codecov Report

Merging #6052 (a35d1ea) into master (6fb395f) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #6052   +/-   ##
=======================================
  Coverage   40.97%   40.97%           
=======================================
  Files         147      147           
  Lines       19691    19691           
=======================================
  Hits         8069     8069           
  Misses      10518    10518           
  Partials     1104     1104           

Impacted Files	Coverage Δ
util/settings/settings.go	41.46% <0.00%> (ø)

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[alexmt]

LGTM. thank you!