Documentation is insufficient

Hello, the documentation says that this plugin needs to be configured in `/opt/graylog/conf/graylog.conf`, but it dose not say anything about acceptable Keys or Values.

I read the source code and guessed at the following config key=value's

otx_enabled = true # boolean otxEnabled
otx_api_key = 5f554abe80f4fc75815904be89621f096c77ec2cb58ca449f57061a0db2cb31a # @Nullable String otxApiKey
tor_enabled = true # boolean torEnabled
spamhaus_enabled = true # boolean spamhausEnabled
abusech_ransom_enabled = true # boolean abusechransomEnabled

I then ran `sudo graylog-ctl restart` a couple times.

None of the example Search strings in the Readme.md have any effect. There are no new values added to the output, and no indication that anything at all happened.