closes #42

This PR initializes a react app and embeds it successfully into the gokakashi binary. That way, our gokakashi server can serve the frontend from the same binary.

A blog post about the learnings from here: https://vishnubharathi.codes/blog/baking-a-react-app-into-a-go-server/

This PR also originates this work: #51 (that I would like to tackle in a future point in time)

Running just the webserver

$ WEB_ONLY=1 go run main.go server
2024/12/21 08:17:38 Starting webapp server at :5555
^C
interrupt
2024/12/21 08:17:41 Exiting gokakashi. Bye!