Add a line for "ca-dir" settings in the configmap of eck-operator

[sebgamby]

Proposal

Add a line in deploy/eck-operator/templates/configmap.yaml for the setting "ca-dir"

Use case. Why is this important?
It is convenient to let the ECK operator manage the certificates for the HTTP services of ElasticSearch and the Fleet agents on basis of a provided CA certificate and key because I can then easily provide this CA certificate to the applications calling those services for validating the server identity.

Currently, I am creating the ECK operator with the published manifest files but I would prefer to use the Helm chart. The lack of this setting is however blocking me.