Configure envoy's idle_timeout for TCP

#### Feature Description

Provide a way or an example to set envoy's [idle_timeout](https://www.envoyproxy.io/docs/envoy/latest/api-v3/extensions/filters/network/tcp_proxy/v3/tcp_proxy.proto#envoy-v3-api-field-extensions-filters-network-tcp-proxy-v3-tcpproxy-idle-timeout)

#### Use Case(s)

I’m having a TCP keep-alive issue, idle connections get disconnected by the proxy after an hour, and I want to overwrite `idle_timeout` either at service definition or globally.

I saw some examples like the one below, but It’s not clear to me if this `envoy_public_listener_json` will overwrite the service name/port that was defined at the `sidecar_service` level?

```
{
"service": {
"name": "test",
"connect": {
"sidecar_service": {
"port": "xxxx",
"proxy": {
"upstreams": [
{
"destination_name": "xxxxx",
"local_bind_port": "xxxxx",
"config": {
envoy_public_listener_json= <

Start by reviewing the envoy_public_listener_json example alongside the sidecar_service and proxy.upstreams configuration shown in the issue. Determine whether idle_timeout can be configured at service or global scope without changing the defined service and port; done means documenting a supported configuration or example that answers those interactions.

Written by the indexing model from the issue text.