Clarify hostname and service name in external mongod search snippets

[anandsyncs]

Summary

This pull request updates the configuration and code snippets for setting up an external MongoDB Search service to improve clarity and consistency in variable naming. The main change is the introduction of the MDB_SEARCH_SERVICE_NAME variable, replacing the previous use of MDB_SEARCH_HOSTNAME for Kubernetes service references, while MDB_SEARCH_HOSTNAME is now used specifically for the DNS hostname.

Configuration variable updates:

• Introduced MDB_SEARCH_SERVICE_NAME to represent the Kubernetes service name and updated all related references in env_variables.sh and README.md. The MDB_SEARCH_HOSTNAME variable is now used to specify the DNS hostname (e.g., mdbs-search.example.com). [1] [2]

Kubernetes service creation and referencing:

• Updated service creation in 04_0322_create_search_loadbalancer_service.sh to use MDB_SEARCH_SERVICE_NAME for the service name instead of MDB_SEARCH_HOSTNAME.
• Changed all kubectl commands and log messages in scripts to reference MDB_SEARCH_SERVICE_NAME instead of MDB_SEARCH_HOSTNAME, ensuring consistency throughout the deployment process. [1] [2]

Proof of Work

Snippet tests pass

Checklist

• Have you linked a jira ticket and/or is the ticket in the title?
• Have you checked whether your jira ticket required DOCSP changes?
• Have you added changelog file?
  • use skip-changelog label if not needed
  • refer to Changelog files and Release Notes section in CONTRIBUTING.md for more details

[github-actions]

⚠️ (this preview might not be accurate if the PR is not rebased on current master branch)

MCK 1.5.0 Release Notes

New Features

• Improve automation agent certificate rotation: the agent now restarts automatically when its certificate is renewed, ensuring smooth operation without manual intervention and allowing seamless certificate updates without requiring manual Pod restarts.

[lsierant]

we should probably remove that readme completely?