Add Secure Devutils tools to README

[RajendraNittala]

Secure Devutils - a collection of 30+ privacy-first, fully client-side developer tools with offline PWA support and free.

[github-actions]

Hey RajendraNittala! Thanks for your submission! 🚀

To keep awesome-devtools instantly accessible for everyone, all tools must be:

• Browser-based — no downloads or native app installs
• Direct link — goes straight to the tool (not a multi-tool landing page)
• 100% free — no signups, trials, paywalls, or usage limits

Please make sure your PR meets these criteria. It may take some time for your submission to be reviewed — you can occasionally comment with a "bump" to bring more attention to it.

Thanks for contributing! 🙌

[moimikey]

Thanks for the contribution! Closing this one — per CONTRIBUTING.md, entries should be direct, single-purpose tool links rather than multi-tool suites or landing pages, and we recently trimmed vendor bundles and duplicates to keep the list focused. If there's a single standout tool here that nothing else on the list covers, feel free to open a fresh PR for just that one. Appreciate the effort!