feat: migrate Cloudflare jobs from gitlab-web-ide-vscode-fork

What does this MR do and why?

This MR migrates the Cloudflare jobs from the old gitlab-web-ide-vscode-fork repository.

There are two jobs for each environment (staging/production):

• deploy-assets-<env> - copies tmp/packages/gitlab-web-ide-vscode-workbench-* to the Cloudflare R2 bucket.
• deploy-cloudflare-worker-<env> - deploys Cloudflare worker if there are changes to the cloudflare/* files.

Both jobs have been tested in staging (example URL that now works: https://random-string.staging.cdn.web-ide.gitlab-static.net/gitlab-web-ide-vscode-workbench-0.0.1-dev-20250318050151/vscode/out/vs/code/browser/workbench/workbench.html).

Infra issue: gitlab-com/gl-infra/production-engineering#26356 (closed)
Requested in #449 (closed).

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