feat: first basic draft of the registry plugin

[nigelhanlon]

This PR aims to track the development of the initial registry reporter plugin.

The goals are:

• To develop a fastify plugin that integrates with Mercurius (see plugins here)
• Report the currently loaded schema in Mercurius to the Apollo Registry.

Tasks and Remaining Development

• [x] Implement minimum viable plugin that can report to the registry
• [x] Update plugin to require Mercurius as a dependency
• [x] Use fastify hooks to ensure our schema has settled and fastify has actually started.
• [x] Replace timeout function with util.promisify version.
• [x] Update normalizeSchema with basic white space removal.
• [x] Replace console loggers with the correct fastify equivalent
• [x] Add tests, mocking responses from the registry. Apollo implementation has good examples.
• [x] Add linting and commit hooks (husky/eslint) (@nigelhanlon check how other plugins do it. most of them use standard for js style)
• [x] setup CI with gh actions and dependabot with automerge (inspire from how existing plugins do it)
• [ ] publish plugin to npm registry
• [ ] include plugin in mercurius docs
• [ ] move plugin to mercurius organization (check with @mcollina )
• [ ] track points for improvements in new issues (configurable interval for schema publishing, ...)