Simplify examples and move them into related connector repo

[enocom]

Description

We have a connector for Go, Python, and Java which are better places to store examples for how to connect over TCP.

Node.js will remain here for now.

Potential Solution

Instead of an entire sample app, we only need to show to connect and query.

Additional Details

Samples are used here: https://cloud.google.com/alloydb/docs/auth-proxy/connect#connect-application.