[Feature]: Add existingSecret for the storage.elasticsearch configuration

[menvol3]

Requirement

Add the ability to set a password via secretKeyRef for the elasticsearch storage, as it is done for Cassandra
https://github.com/jaegertracing/helm-charts/blame/main/charts/jaeger/templates/_helpers.tpl#L165

Problem

The previous logic for existingSecret was removed
https://github.com/jaegertracing/helm-charts/blob/7137582c80e15531bb253dcdff7c25a18dbfbb2c/charts/jaeger/templates/elasticsearch-secret.yaml

Proposal

Reuse existing logic from the Cassandra configuration

Open questions

No response

[pschichtel]

this would be awesome for people using the ECK operator to deploy ES clusters.