ROX-31487: Add helm chart

[mtodor]

Description

This PR is adding helm chart from StackRox MCP server

Additional changes:

• additional style checks are added for helm template
• Dockerfile is modified to better support Openshift security context constraints (SCCs)

Validation

• usual helm lint (part of CI)
• deploy on Openshift cluster and test
• test new Dockerfile
• deploy on GKE cluster and test

An example command to deploy helm:

helm upgrade --install stackrox-mcp charts/stackrox-mcp \
  --namespace stackrox-mcp-helm \
  --create-namespace \
  --set config.tools.vulnerability.enabled=true \
  --set config.central.url=<Central URL>:443 \
  --set image.tag=<Image Tag> \
  --set config.central.insecureSkipTLSVerify=true

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 77.36%. Comparing base (53e4b0b) to head (7f29fda).
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@           Coverage Diff           @@
##             main      #23   +/-   ##
=======================================
  Coverage   77.36%   77.36%           
=======================================
  Files          26       26           
  Lines        1109     1109           
=======================================
  Hits          858      858           
  Misses        216      216           
  Partials       35       35           

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[mtodor]

This is fixed now.