Port-forward debug endpoints only when running odo dev with --debug

[rm3l]

/kind feature
/area dev

Which functionality do you think we should add?

I think we should port-forward debug endpoints only when running odo dev --debug.
As discussed in #5988 (comment), we should have a way to identify Debug endpoints.

Why is this needed?

At this time, when running odo dev against a Devfile with a Debug endpoint, all endpoints are port-forwarded, including the debug endpoint.
But when trying (intentionally or not) to reach the corresponding local port, we might get an error because the container may not be listening on the debug port (because we are not running the debug command); as a consequence, port-forwarding is restarted.
Worse, if running odo dev --random-ports, new local random ports get generated.

# Sample project
odo init \
  --devfile-path https://raw.githubusercontent.com/redhat-developer/odo/main/tests/examples/source/devfiles/nodejs/devfile-with-debugrun.yaml \
  --starter nodejs-starter \
  --name nodejs-starter

# Dev Session
odo dev

# Once Dev Session is running, try to access the port-forwarded for the debug endpoint (5858), say: 40002
# This local port will never be reachable unless we stop `odo dev` and run `odo dev --debug` instead.

Related: devfile/registry#122 (comment)