Add Typescript definitions

[mnlfischer]

🚀 Feature Proposal

Add missing Typescript definitions.

Motivation

I would like to use fastify-routes in a Typescript project, especially for testing registered routes. I did not found any type definitions in this project or some definitions from https://www.npmjs.com/~types.

Would be happy if you can support Typescript in the future. I'm not so deep into TS definitions but with some practice I can support.

Example

No example needed.

[mcollina]

Would you like to send a Pull Request to address this issue? Remember to add unit tests.

Use fastify-static as a starting point.

[mnlfischer]

I'm on vacation for the next two weeks. I look at it after.

[Fdawgs]

@mnlfischer has #44 resolved this?