feat: Generate Tests for new middleware or routes

[jxstxn1]

Description

As a User I would love to get generated Tests for new routes/middlewares each time I run dart_frog new middleware [routeName] or dart_frog new routes [routeName]. This can save me some time so that I don't have to create the tests manually.

Requirements

• [ ] create tests for newly generated routes or middlewares

Additional Context It could be even more beneficial to have this feature once dart_frog_test is released

[erickzanardo]

That is a great idea! We are actively working on dart_frog_test and once we have definition about that package, we can come back to this one.