[OpenSearch] Extend/new OpenSearch Kubernetes operator for maintenance tasks

[Kuckkuck]

At the moment we need additional steps in the pipeline and/or in the helm-chart to configure an OpenSearch database, maybe we can put this additional steps somehow into an operator. The following steps need to be implemented:

• create users in vault or any other password tool
• naming schema for index names and usernames to make the configuration for the log shippers simple.
• creation of roles, roles_mapping and internal_users. The password of the internal user needs to be hashed by an internal OpenSearch tool provided by any OpenSearch image, scripted called hash.sh
• Upload of all security configuration, after the database was created to make the database usable. This upload procedure also needs an internal OpenSearch script, called admin.sh. This script uses the admin.cert + admin.key to upload all configured security configs to the cluster. It is also used for updates to roles, internal_users, mappings etc...
• Upload of index/datastream templates for index settings like sharding, backup shards, mappings etc.
• Upload of ISM templates, index lifecycle management templates for handling rentention, archiving etc