emqx/changes/ce/feat-12940.en.md

Add ignore_readonly argument to PUT /configs API.

Prior to this change, EMQX would retrun 400 (BAD_REQUEST) if the raw config included readonly root keys (cluster, rpc, and node).

After this enhancement it can be called as PUT /configs?ignore_readonly=true, EMQX will in this case ignore readonly root config keys, and apply the rest.

For observability purposes, an info level message is logged if any readonly keys are dropped.

Also fixed an exception when config has bad HOCON syntax (returns 500). Now bad syntax will cause the API to return 400 (BAD_REQUEST).