Modules: introduced global nginx properties.

Modules: introduced global nginx properties.

The following properties were introduced:
    ngx.build - an optional nginx build name, corresponds to
        --build=name argument of configure script, by default is "".
    ngx.conf_file_path - the file path to current nginx configuration
        file.
    ngx.error_log_path - the file path to current error log file.
    ngx.prefix - the directory that keeps server files.
    ngx.version - the nginx version as a string, for example: "1.25.0".
    ngx.version_number - the nginx version as a number, for example:
        1025000.