Add OpsCanopy to Continuous Integration & Delivery

[PushkarMandark]

Adds OpsCanopy, a set of 29 browser-based DevOps utilities.

Relevant to this section: GitHub Actions workflow validator, GitHub Actions
expression and trigger tester, GitLab CI validator, and a Docker run to Compose
converter. Others cover observability (PromQL, LogQL, Alertmanager routing,
Prometheus relabeling), networking (subnet, CIDR, PTR) and encoding.

Everything runs client-side with no signup and no upload — the site's CSP sets
connect-src 'self', so pasted configs cannot leave the browser. That is the
main reason it exists: the equivalent hosted validators all POST your CI config
to a server, which is awkward when it contains internal hostnames and secret
names.

Disclosure: I built this.

[PushkarMandark]

Closing in favour of #501, which adds OpsCanopy to Productivity Tools — a better fit for a tool catalogue than CI/CD, and CONTRIBUTING asks for consolidated submissions rather than one PR per category. #501 has also been updated to meet the <80 character description guideline. Sorry for the noise.