Feature: Configurable Log Level

Would like this to be a environment variable we can set:

https://github.com/SpiderLabs/ModSecurity-nginx/blob/master/src/ngx_http_modsecurity_log.c#L33

ngx_log_error(NGX_LOG_INFO, (ngx_log_t *)log, 0, "%s", msg);

NGX_LOG_INFO is nice and appropriate likely for warning messages generally speaking. But info in many NGX deployments is too noisy regarding other things, so it would be nice if this was default to INFO but I could pick ERROR or DEBUG or NOTICE etc. Right now I drop in a patch file and run this line as:

ngx_log_error(NGX_LOG_ERROR, (ngx_log_t *)log, 0, "%s", msg);

Because that is the log level I want WAF detection information to run on for my use case.