config/plugin_cache: Add specific error for `global` and `config` entries
config/plugin_cache: Add specific error for `global` and `config` entries

Add a special error for finding `global` or `config``  entries in
configuration to provide a more helpful error message.

ARM-software/workload-automation,ARM-software/workload-automation,setrofim/workload-automation,setrofim/workload-automation,lisatn/workload-automation,ARM-software/workload-automation,setrofim/workload-automation,ARM-software/workload-automation,setrofim/workload-automation,lisatn/workload-automation,lisatn/workload-automation,lisatn/workload-automation