Improve integration summaries

[moshloop]

The integration pages serve 2 purposes:

1. Inform users what and how the integration works
2. Sell the benefits of the inregration to potential new users reviewing the docs to see how it works.

Make each integration page:

1. Use consistent style, tone, and language ( in addition to complying with all the Vale rules and definitions)
2. Have a structiured approach to each page that begins by making no assumptions of what the integrations and what mission control is (besides for the main overview page) as you scroll down it becomes more practical

[DYTechWriter]

PR #510 covers 8 of 29 integration pages as an initial batch:

ArgoCD
Azure
Azure DevOps
ClickHouse
Kubernetes
GitHub
Prometheus
Slack

Each page now opens with a brief, assumption-free description of the tool itself before explaining how Mission Control integrates with it. Remaining pages can be addressed in the same PR or follow-up PRs.