feat: Send the metrics to an api

[ats0405]

Problem At the moment, the metrics generated are not send to a custom API created by developers.

Solution

• Give developers an option to send web-vitals metrics to an endpoint.
• I have added an example in the playground. In this example, the metrics are send to a server middleware with the endpoint /analytics.

[woile]

Hey @pi0 do you think you could take a look at this PR? Do you think it's in the right direction, I'm interested in it.

Thanks a lot 🙏🏻

[pi0]

Thanks for PR @ats0405 ❤️