Expose TLS from Connect sidecar proxy

#### Feature Description

Connect sidecar proxies transparently provides mTLS between services while terminating TLS on either end. It would be great if exposed http/websockets endpoints can be exposed to downstream with TLS

#### Use Case(s)

Legacy applications where downstream requires encryption while upstream does not support it. This can of course be solved by inserting another proxy or LB between the two, but it would be very nice if this use-case could be sorted out by Connect.

---

Maybe this is already possible by tweaking the envoy sidecar proxy configurations, in which case this should be changed to a [docs] issue