feat: Add NIC LTS documentation

[JTorreG]

Proposed changes

NGINX Ingress Controller LTS (Long Term Support) documentation

This is a WIP branch. Make updates to the LTS docs by branching out from nic/LTS and targeting it for merge.

Checklist

Before sharing this pull request, I completed the following checklist:

• I read the Contributing guidelines
• My branch adheres to the Git conventions
• My content changes adhere to the F5 Technical Writing Style Guide
• If my changes involve potentially sensitive information¹, I have assessed the possible impact
• I have waited to ensure my changes pass tests, and addressed any discovered issues

Footnotes

1. Potentially sensitive information includes personally identify information (PII), authentication credentials, and live URLs. Refer to the style guide for guidance about placeholder content. ↩

[github-actions]

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[JTorreG]

modified files so far:

  Modified:
  nic/lts/overview/about.md
  nic/lts/overview/design.md
  nic/lts/technical-specifications.md
  nic/lts/install/images/registry-download.md
  nic/lts/install/images/add-image-to-cluster.md
  nic/lts/install/helm/plus.md
  nic/lts/install/helm/parameters.md
  nic/lts/install/manifests.md
  nic/lts/install/build.md
  nic/lts/install/license-secret.md
  nic/lts/install/upgrade.md
  nic/lts/install/operator.md
  nic/lts/install/waf-helm.md
  nic/lts/configuration/global-configuration/command-line-arguments.md
  nic/lts/integrations/app-protect-waf-v5/installation.md
  nic/lts/integrations/app-protect-dos/installation.md
  nic/lts/logging-and-monitoring/prometheus.md
  nic/lts/troubleshooting/troubleshoot-common.md
  nic/lts/tutorials/custom-listen-ports.md
  nic/lts/tutorials/ingress-path-regex-annotation.md

  Deleted:
  nic/lts/install/helm/open-source.md
  nic/lts/logging-and-monitoring/opentracing.md
  nic/lts/integrations/app-protect-waf/_index.md
  nic/lts/integrations/app-protect-waf/installation.md
  nic/lts/integrations/app-protect-waf/configuration.md
  nic/lts/usage-reporting.md