how about deny some plugins config when APISIX-OpenResty is missed?

[RocFang]

Some plugins need APISIX-OpenResty, for example client-contol etc.

currently, user can still enable them, and retun 501 when access.

Maybe it's more friendly to deny the config request at first like jsonschema?

for example, add a local bolean module-level viable in these plugins, and check it right before of after check_schema.

[spacewander]

Deny the config during checking the schema may bring inconvenience when we are doing A/B testing.