IBLPLATFRM-302: Convert repo to pnpm

[cjewell47]

Convert repo to use pnpm instead of npm.
Generated by https://github.com/bbc/ibl-scripts/blob/main/node/gh-tools/pnpm-conversion.ts.
https://bbc.atlassian.net/browse/IBLPLATFRM-302
- Added pnpm-workspace.yaml
- Removed package-lock.json
- pnpm import
- Converted npm and npx usage
- Installed dev dependencies: audit-ci

[github-actions]

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