Since these worked in v23.08, we can't just rename them. So if they are
used and unclaimed, we should rename them internally (if they're claimed,
it's probably clightning-rest, and we should *NOT* touch them!).
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Changelog-Deprecated: Plugins: `clnrest` parameters `rest-port`, `rest-protocol`, `rest-host` and `rest-certs`: prefix `cln` to them
