Is your feature request related to a problem? Please describe.

Now the otel collector supports config reloading via SIGHUP, as implemented in #6000.

But it is hard to send SIGHUP to process when it's deployed in k8s.

Related issue: #5966

Describe the solution you'd like

Support trigger config reloading via HTTP request, for example:

curl -X POST <host>:<port>/-/reload

Some other popular softwares like promethus and alertmanager support this feature as well:

• prometheus: https://www.robustperception.io/reloading-prometheus-configuration/
• alertmanager: https://prometheus.io/docs/alerting/latest/management_api/#reload

If this feature is implemented, we can deploy otel-collector with configmap-reload as a sidecar, so that when config map is changed, the otel-collector can get a HTTP request then reload its config.